NAME
Text::CSV_XS - comma-separated values manipulation routines
SYNOPSIS
# Functional interface
use Text::CSV_XS qw( csv );
# Read whole file in memory
my $aoa = csv (in => "data.csv"); # as array of array
my $aoh = csv (in => "data.csv",
headers => "auto"); # as array of hash
# Write array of arrays as csv file
csv (in => $aoa, out => "file.csv", sep_char=> ";");
# Only show lines where "code" is odd
csv (in => "data.csv", filter => { code => sub { $_ % 2 }});
# Object interface
use Text::CSV_XS;
my @rows;
# Read/parse CSV
my $csv = Text::CSV_XS->new ({ binary => 1, auto_diag => 1 });
open my $fh, "<:encoding(utf8)", "test.csv" or die "test.csv: $!";
while (my $row = $csv->getline ($fh)) {
$row->[2] =~ m/pattern/ or next; # 3rd field should match
push @rows, $row;
}
close $fh;
# and write as CSV
open $fh, ">:encoding(utf8)", "new.csv" or die "new.csv: $!";
$csv->say ($fh, $_) for @rows;
close $fh or die "new.csv: $!";
DESCRIPTION
Text::CSV_XS provides facilities for the composition and decomposition of comma-separated values. An instance of the Text::CSV_XS class will combine fields into a CSV
string and parse a CSV
string into fields.
The module accepts either strings or files as input and support the use of user-specified characters for delimiters, separators, and escapes.
Embedded newlines
Important Note: The default behavior is to accept only ASCII characters in the range from 0x20
(space) to 0x7E
(tilde). This means that the fields can not contain newlines. If your data contains newlines embedded in fields, or characters above 0x7E
(tilde), or binary data, you must set binary => 1
in the call to "new". To cover the widest range of parsing options, you will always want to set binary.
But you still have the problem that you have to pass a correct line to the "parse" method, which is more complicated from the usual point of usage:
my $csv = Text::CSV_XS->new ({ binary => 1, eol => $/ });
while (<>) { # WRONG!
$csv->parse ($_);
my @fields = $csv->fields ();
}
this will break, as the while
might read broken lines: it does not care about the quoting. If you need to support embedded newlines, the way to go is to not pass eol
in the parser (it accepts \n
, \r
, and \r\n
by default) and then
my $csv = Text::CSV_XS->new ({ binary => 1 });
open my $io, "<", $file or die "$file: $!";
while (my $row = $csv->getline ($io)) {
my @fields = @$row;
}
The old(er) way of using global file handles is still supported
while (my $row = $csv->getline (*ARGV)) { ... }
Unicode
Unicode is only tested to work with perl-5.8.2 and up.
On parsing (both for "getline" and "parse"), if the source is marked being UTF8, then all fields that are marked binary will also be marked UTF8.
For complete control over encoding, please use Text::CSV::Encoded:
use Text::CSV::Encoded;
my $csv = Text::CSV::Encoded->new ({
encoding_in => "iso-8859-1", # the encoding comes into Perl
encoding_out => "cp1252", # the encoding comes out of Perl
});
$csv = Text::CSV::Encoded->new ({ encoding => "utf8" });
# combine () and print () accept *literally* utf8 encoded data
# parse () and getline () return *literally* utf8 encoded data
$csv = Text::CSV::Encoded->new ({ encoding => undef }); # default
# combine () and print () accept UTF8 marked data
# parse () and getline () return UTF8 marked data
On combining ("print" and "combine"): if any of the combining fields was marked UTF8, the resulting string will be marked as UTF8. Note however that all fields before the first field marked UTF8 and contained 8-bit characters that were not upgraded to UTF8, these will be bytes
in the resulting string too, possibly causing unexpected errors. If you pass data of different encoding, or you don't know if there is different encoding, force it to be upgraded before you pass them on:
$csv->print ($fh, [ map { utf8::upgrade (my $x = $_); $x } @data ]);
SPECIFICATION
While no formal specification for CSV exists, RFC 4180 1) describes the common format and establishes text/csv
as the MIME type registered with the IANA. RFC 7111 2 adds fragments to CSV.
Many informal documents exist that describe the CSV
format. "How To: The Comma Separated Value (CSV) File Format" 3) provides an overview of the CSV
format in the most widely used applications and explains how it can best be used and supported.
1) http://tools.ietf.org/html/rfc4180
2) http://tools.ietf.org/html/rfc7111
3) http://www.creativyst.com/Doc/Articles/CSV/CSV01.htm
The basic rules are as follows:
CSV is a delimited data format that has fields/columns separated by the comma character and records/rows separated by newlines. Fields that contain a special character (comma, newline, or double quote), must be enclosed in double quotes. However, if a line contains a single entry that is the empty string, it may be enclosed in double quotes. If a field's value contains a double quote character it is escaped by placing another double quote character next to it. The CSV
file format does not require a specific character encoding, byte order, or line terminator format.
Each record is a single line ended by a line feed (ASCII/
LF
=0x0A
) or a carriage return and line feed pair (ASCII/CRLF
=0x0D 0x0A
), however, line-breaks may be embedded.Fields are separated by commas.
Allowable characters within a
CSV
field include0x09
(TAB
) and the inclusive range of0x20
(space) through0x7E
(tilde). In binary mode all characters are accepted, at least in quoted fields.A field within
CSV
must be surrounded by double-quotes to contain a separator character (comma).
Though this is the most clear and restrictive definition, Text::CSV_XS is way more liberal than this, and allows extension:
Line termination by a single carriage return is accepted by default
The separation-, escape-, and escape- characters can be any ASCII character in the range from
0x20
(space) to0x7E
(tilde). Characters outside this range may or may not work as expected. Multibyte characters, like UTFU+060C
(ARABIC COMMA),U+FF0C
(FULLWIDTH COMMA),U+241B
(SYMBOL FOR ESCAPE),U+2424
(SYMBOL FOR NEWLINE),U+FF02
(FULLWIDTH QUOTATION MARK), andU+201C
(LEFT DOUBLE QUOTATION MARK) (to give some examples of what might look promising) work for newer versions of perl forsep_char
, andquote_char
but not forescape_char
.If you use perl-5.8.2 or higher these three attributes are utf8-decoded, to increase the likelihood of success. This way
U+00FE
will be allowed as a quote character.A field in
CSV
must be surrounded by double-quotes to make an embedded double-quote, represented by a pair of consecutive double-quotes, valid. In binary mode you may additionally use the sequence"0
for representation of a NULL byte. Using0x00
in binary mode is just as valid.Several violations of the above specification may be lifted by passing some options as attributes to the object constructor.
METHODS
version
(Class method) Returns the current module version.
new
(Class method) Returns a new instance of class Text::CSV_XS. The attributes are described by the (optional) hash ref \%attr
.
my $csv = Text::CSV_XS->new ({ attributes ... });
The following attributes are available:
eol
my $csv = Text::CSV_XS->new ({ eol => $/ });
$csv->eol (undef);
my $eol = $csv->eol;
The end-of-line string to add to rows for "print" or the record separator for "getline".
When not passed in a parser instance, the default behavior is to accept \n
, \r
, and \r\n
, so it is probably safer to not specify eol
at all. Passing undef
or the empty string behave the same.
When not passed in a generating instance, records are not terminated at all, so it is probably wise to pass something you expect. A safe choice for eol
on output is either $/
or \r\n
.
Common values for eol
are "\012"
(\n
or Line Feed), "\015\012"
(\r\n
or Carriage Return, Line Feed), and "\015"
(\r
or Carriage Return). The eol
attribute cannot exceed 7 (ASCII) characters.
If both $/
and eol
equal "\015"
, parsing lines that end on only a Carriage Return without Line Feed, will be "parse"d correct.
sep_char
my $csv = Text::CSV_XS->new ({ sep_char => ";" });
$csv->sep_char (";");
my $c = $csv->sep_char;
The char used to separate fields, by default a comma. (,
). Limited to a single-byte character, usually in the range from 0x20
(space) to 0x7E
(tilde). When longer sequences are required, use sep
.
The separation character can not be equal to the quote character or to the escape character.
See also "CAVEATS"
sep
my $csv = Text::CSV_XS->new ({ sep => "\N{FULLWIDTH COMMA}" });
$csv->sep (";");
my $sep = $csv->sep;
The chars used to separate fields, by default undefined. Limited to 8 bytes.
When set, overrules sep_char
. If its length is one byte it acts as an alias to sep_char
.
See also "CAVEATS"
quote_char
my $csv = Text::CSV_XS->new ({ quote_char => "'" });
$csv->quote_char (undef);
my $c = $csv->quote_char;
The character to quote fields containing blanks or binary data, by default the double quote character ("
). A value of undef suppresses quote chars (for simple cases only). Limited to a single-byte character, usually in the range from 0x20
(space) to 0x7E
(tilde). When longer sequences are required, use quote
.
quote_char
can not be equal to sep_char
.
quote
my $csv = Text::CSV_XS->new ({ quote => "\N{FULLWIDTH QUOTATION MARK}" });
$csv->quote ("'");
my $quote = $csv->quote;
The chars used to quote fields, by default undefined. Limited to 8 bytes.
When set, overrules quote_char
. If its length is one byte it acts as an alias to quote_char
.
See also "CAVEATS"
escape_char
my $csv = Text::CSV_XS->new ({ escape_char => "\\" });
$csv->escape_char (undef);
my $c = $csv->escape_char;
The character to escape certain characters inside quoted fields. This is limited to a single-byte character, usually in the range from 0x20
(space) to 0x7E
(tilde).
The escape_char
defaults to being the double-quote mark ("
). In other words the same as the default quote_char
. This means that doubling the quote mark in a field escapes it:
"foo","bar","Escape ""quote mark"" with two ""quote marks""","baz"
If you change the quote_char
without changing the escape_char
, the escape_char
will still be the double-quote ("
). If instead you want to escape the quote_char
by doubling it you will need to also change the escape_char
to be the same as what you have changed the quote_char
to.
The escape character can not be equal to the separation character.
binary
my $csv = Text::CSV_XS->new ({ binary => 1 });
$csv->binary (0);
my $f = $csv->binary;
If this attribute is 1
, you may use binary characters in quoted fields, including line feeds, carriage returns and NULL
bytes. (The latter could be escaped as "0
.) By default this feature is off.
If a string is marked UTF8, binary
will be turned on automatically when binary characters other than CR
and NL
are encountered. Note that a simple string like "\x{00a0}"
might still be binary, but not marked UTF8, so setting { binary => 1 }
is still a wise option.
decode_utf8
my $csv = Text::CSV_XS->new ({ decode_utf8 => 1 });
$csv->decode_utf8 (0);
my $f = $csv->decode_utf8;
This attributes defaults to TRUE.
While parsing, fields that are valid UTF-8, are automatically set to be UTF-8, so that
$csv->parse ("\xC4\xA8\n");
results in
PV("\304\250"\0) [UTF8 "\x{128}"]
Sometimes it might not be a desired action. To prevent those upgrades, set this attribute to false, and the result will be
PV("\304\250"\0)
auto_diag
my $csv = Text::CSV_XS->new ({ auto_diag => 1 });
$csv->auto_diag (2);
my $l = $csv->auto_diag;
Set this attribute to a number between 1
and 9
causes "error_diag" to be automatically called in void context upon errors.
In case of error 2012 - EOF
, this call will be void.
If auto_diag
is set to a numeric value greater than 1
, it will die
on errors instead of warn
. If set to anything unrecognized, it will be silently ignored.
Future extensions to this feature will include more reliable auto-detection of autodie
being active in the scope of which the error occurred which will increment the value of auto_diag
with 1
the moment the error is detected.
diag_verbose
my $csv = Text::CSV_XS->new ({ diag_verbose => 1 });
$csv->diag_verbose (2);
my $l = $csv->diag_verbose;
Set the verbosity of the output triggered by auto_diag
. Currently only adds the current input-record-number (if known) to the diagnostic output with an indication of the position of the error.
blank_is_undef
my $csv = Text::CSV_XS->new ({ blank_is_undef => 1 });
$csv->blank_is_undef (0);
my $f = $csv->blank_is_undef;
Under normal circumstances, CSV
data makes no distinction between quoted- and unquoted empty fields. These both end up in an empty string field once read, thus
1,"",," ",2
is read as
("1", "", "", " ", "2")
When writing CSV
files with always_quote
set, the unquoted empty field is the result of an undefined value. To enable this distinction when reading CSV
data, the blank_is_undef
attribute will cause unquoted empty fields to be set to undef
, causing the above to be parsed as
("1", "", undef, " ", "2")
empty_is_undef
my $csv = Text::CSV_XS->new ({ empty_is_undef => 1 });
$csv->empty_is_undef (0);
my $f = $csv->empty_is_undef;
Going one step further than blank_is_undef
, this attribute converts all empty fields to undef
, so
1,"",," ",2
is read as
(1, undef, undef, " ", 2)
Note that this effects only fields that are originally empty, not fields that are empty after stripping allowed whitespace. YMMV.
allow_whitespace
my $csv = Text::CSV_XS->new ({ allow_whitespace => 1 });
$csv->allow_whitespace (0);
my $f = $csv->allow_whitespace;
When this option is set to true, the whitespace (TAB
's and SPACE
's) surrounding the separation character is removed when parsing. If either TAB
or SPACE
is one of the three characters sep_char
, quote_char
, or escape_char
it will not be considered whitespace.
Now lines like:
1 , "foo" , bar , 3 , zapp
are parsed as valid CSV
, even though it violates the CSV
specs.
Note that all whitespace is stripped from both start and end of each field. That would make it more than a feature to enable parsing bad CSV
lines, as
1, 2.0, 3, ape , monkey
will now be parsed as
("1", "2.0", "3", "ape", "monkey")
even if the original line was perfectly acceptable CSV
.
allow_loose_quotes
my $csv = Text::CSV_XS->new ({ allow_loose_quotes => 1 });
$csv->allow_loose_quotes (0);
my $f = $csv->allow_loose_quotes;
By default, parsing unquoted fields containing quote_char
characters like
1,foo "bar" baz,42
would result in parse error 2034. Though it is still bad practice to allow this format, we cannot help the fact that some vendors make their applications spit out lines styled this way.
If there is really bad CSV
data, like
1,"foo "bar" baz",42
or
1,""foo bar baz"",42
there is a way to get this data-line parsed and leave the quotes inside the quoted field as-is. This can be achieved by setting allow_loose_quotes
AND making sure that the escape_char
is not equal to quote_char
.
allow_loose_escapes
my $csv = Text::CSV_XS->new ({ allow_loose_escapes => 1 });
$csv->allow_loose_escapes (0);
my $f = $csv->allow_loose_escapes;
Parsing fields that have escape_char
characters that escape characters that do not need to be escaped, like:
my $csv = Text::CSV_XS->new ({ escape_char => "\\" });
$csv->parse (qq{1,"my bar\'s",baz,42});
would result in parse error 2025. Though it is bad practice to allow this format, this attribute enables you to treat all escape character sequences equal.
allow_unquoted_escape
my $csv = Text::CSV_XS->new ({ allow_unquoted_escape => 1 });
$csv->allow_unquoted_escape (0);
my $f = $csv->allow_unquoted_escape;
A backward compatibility issue where escape_char
differs from quote_char
prevents escape_char
to be in the first position of a field. If quote_char
is equal to the default "
and escape_char
is set to \
, this would be illegal:
1,\0,2
Setting this attribute to 1
might help to overcome issues with backward compatibility and allow this style.
always_quote
my $csv = Text::CSV_XS->new ({ always_quote => 1 });
$csv->always_quote (0);
my $f = $csv->always_quote;
By default the generated fields are quoted only if they need to be. For example, if they contain the separator character. If you set this attribute to 1
then all defined fields will be quoted. (undef
fields are not quoted, see "blank_is_undef"). This makes it quite often easier to handle exported data in external applications. (Poor creatures who are better to use Text::CSV_XS. :)
quote_space
my $csv = Text::CSV_XS->new ({ quote_space => 1 });
$csv->quote_space (0);
my $f = $csv->quote_space;
By default, a space in a field would trigger quotation. As no rule exists this to be forced in CSV
, nor any for the opposite, the default is true for safety. You can exclude the space from this trigger by setting this attribute to 0.
quote_empty
my $csv = Text::CSV_XS->new ({ quote_empty => 1 });
$csv->quote_empty (0);
my $f = $csv->quote_empty;
By default the generated fields are quoted only if they need to be. An empty (defined) field does not need quotation. If you set this attribute to 1
then empty defined fields will be quoted. (undef
fields are not quoted, see "blank_is_undef"). See also always_quote
.
quote_binary
my $csv = Text::CSV_XS->new ({ quote_binary => 1 });
$csv->quote_binary (0);
my $f = $csv->quote_binary;
By default, all "unsafe" bytes inside a string cause the combined field to be quoted. By setting this attribute to 0
, you can disable that trigger for bytes >= 0x7F
.
escape_null or quote_null (deprecated)
my $csv = Text::CSV_XS->new ({ escape_null => 1 });
$csv->escape_null (0);
my $f = $csv->escape_null;
By default, a NULL
byte in a field would be escaped. This option enables you to treat the NULL
byte as a simple binary character in binary mode (the { binary => 1 }
is set). The default is true. You can prevent NULL
escapes by setting this attribute to 0
.
keep_meta_info
my $csv = Text::CSV_XS->new ({ keep_meta_info => 1 });
$csv->keep_meta_info (0);
my $f = $csv->keep_meta_info;
By default, the parsing of input records is as simple and fast as possible. However, some parsing information - like quotation of the original field - is lost in that process. Setting this flag to true enables retrieving that information after parsing with the methods "meta_info", "is_quoted", and "is_binary" described below. Default is false for performance.
If you set this attribute to a value greater than 9, than you can control output quotation style like it was used in the input of the the last parsed record (unless quotation was added because of other reasons).
my $csv = Text::CSV_XS->new ({
binary => 1,
keep_meta_info => 1,
quote_space => 0,
});
my $row = $csv->parse (q{1,,"", ," ",f,"g","h""h",help,"help"});
$csv->print (*STDOUT, \@row);
# 1,,, , ,f,g,"h""h",help,help
$csv->keep_meta_info (11);
$csv->print (*STDOUT, \@row);
# 1,,"", ," ",f,"g","h""h",help,"help"
verbatim
my $csv = Text::CSV_XS->new ({ verbatim => 1 });
$csv->verbatim (0);
my $f = $csv->verbatim;
This is a quite controversial attribute to set, but makes some hard things possible.
The rationale behind this attribute is to tell the parser that the normally special characters newline (NL
) and Carriage Return (CR
) will not be special when this flag is set, and be dealt with as being ordinary binary characters. This will ease working with data with embedded newlines.
When verbatim
is used with "getline", "getline" auto-chomp
's every line.
Imagine a file format like
M^^Hans^Janssen^Klas 2\n2A^Ja^11-06-2007#\r\n
where, the line ending is a very specific "#\r\n"
, and the sep_char is a ^
(caret). None of the fields is quoted, but embedded binary data is likely to be present. With the specific line ending, this should not be too hard to detect.
By default, Text::CSV_XS' parse function is instructed to only know about "\n"
and "\r"
to be legal line endings, and so has to deal with the embedded newline as a real end-of-line
, so it can scan the next line if binary is true, and the newline is inside a quoted field. With this option, we tell "parse" to parse the line as if "\n"
is just nothing more than a binary character.
For "parse" this means that the parser has no more idea about line ending and "getline" chomp
s line endings on reading.
types
A set of column types; the attribute is immediately passed to the "types" method.
callbacks
See the "Callbacks" section below.
accessors
To sum it up,
$csv = Text::CSV_XS->new ();
is equivalent to
$csv = Text::CSV_XS->new ({
eol => undef, # \r, \n, or \r\n
sep_char => ',',
sep => undef,
quote_char => '"',
quote => undef,
escape_char => '"',
binary => 0,
decode_utf8 => 1,
auto_diag => 0,
diag_verbose => 0,
blank_is_undef => 0,
empty_is_undef => 0,
allow_whitespace => 0,
allow_loose_quotes => 0,
allow_loose_escapes => 0,
allow_unquoted_escape => 0,
always_quote => 0,
quote_empty => 0,
quote_space => 1,
escape_null => 1,
quote_binary => 1,
keep_meta_info => 0,
verbatim => 0,
types => undef,
callbacks => undef,
});
For all of the above mentioned flags, an accessor method is available where you can inquire the current value, or change the value
my $quote = $csv->quote_char;
$csv->binary (1);
It is not wise to change these settings halfway through writing CSV
data to a stream. If however you want to create a new stream using the available CSV
object, there is no harm in changing them.
If the "new" constructor call fails, it returns undef
, and makes the fail reason available through the "error_diag" method.
$csv = Text::CSV_XS->new ({ ecs_char => 1 }) or
die "".Text::CSV_XS->error_diag ();
"error_diag" will return a string like
"INI - Unknown attribute 'ecs_char'"
known_attributes
@attr = Text::CSV_CS->known_attributes;
@attr = Text::CSV_CS::known_attributes;
@attr = $csv->known_attributes;
This method will return an ordered list of all the supported attributes as described above. This can be useful for knowing what attributes are valid in classes that use or extend Text::CSV_XS.
$status = $csv->print ($io, $colref);
Similar to "combine" + "string" + "print", but much more efficient. It expects an array ref as input (not an array!) and the resulting string is not really created, but immediately written to the $io
object, typically an IO handle or any other object that offers a "print" method.
For performance reasons print
does not create a result string, so all "string", "status", "fields", and "error_input" methods will return undefined information after executing this method.
If $colref
is undef
(explicit, not through a variable argument) and "bind_columns" was used to specify fields to be printed, it is possible to make performance improvements, as otherwise data would have to be copied as arguments to the method call:
$csv->bind_columns (\($foo, $bar));
$status = $csv->print ($fh, undef);
A short benchmark
my @data = ("aa" .. "zz");
$csv->bind_columns (\(@data));
$csv->print ($io, [ @data ]); # 11800 recs/sec
$csv->print ($io, \@data ); # 57600 recs/sec
$csv->print ($io, undef ); # 48500 recs/sec
say
$status = $csv->say ($io, $colref);
Like print
, but eol
defaults to $\
.
print_hr
$csv->print_hr ($io, $ref);
Provides an easy way to print a $ref
(as fetched with "getline_hr") provided the column names are set with "column_names".
It is just a wrapper method with basic parameter checks over
$csv->print ($io, [ map { $ref->{$_} } $csv->column_names ]);
combine
$status = $csv->combine (@fields);
This method constructs a CSV
record from @fields
, returning success or failure. Failure can result from lack of arguments or an argument that contains an invalid character. Upon success, "string" can be called to retrieve the resultant CSV
string. Upon failure, the value returned by "string" is undefined and "error_input" could be called to retrieve the invalid argument.
string
$line = $csv->string ();
This method returns the input to "parse" or the resultant CSV
string of "combine", whichever was called more recently.
getline
$colref = $csv->getline ($io);
This is the counterpart to "print", as "parse" is the counterpart to "combine": it parses a row from the $io
handle using the "getline" method associated with $io
and parses this row into an array ref. This array ref is returned by the function or undef
for failure. When $io
does not support getline
, you are likely to hit errors.
When fields are bound with "bind_columns" the return value is a reference to an empty list.
The "string", "fields", and "status" methods are meaningless again.
getline_all
$arrayref = $csv->getline_all ($io);
$arrayref = $csv->getline_all ($io, $offset);
$arrayref = $csv->getline_all ($io, $offset, $length);
This will return a reference to a list of getline ($io) results. In this call, keep_meta_info
is disabled. If $offset
is negative, as with splice
, only the last abs ($offset)
records of $io
are taken into consideration.
Given a CSV file with 10 lines:
lines call
----- ---------------------------------------------------------
0..9 $csv->getline_all ($io) # all
0..9 $csv->getline_all ($io, 0) # all
8..9 $csv->getline_all ($io, 8) # start at 8
- $csv->getline_all ($io, 0, 0) # start at 0 first 0 rows
0..4 $csv->getline_all ($io, 0, 5) # start at 0 first 5 rows
4..5 $csv->getline_all ($io, 4, 2) # start at 4 first 2 rows
8..9 $csv->getline_all ($io, -2) # last 2 rows
6..7 $csv->getline_all ($io, -4, 2) # first 2 of last 4 rows
getline_hr
The "getline_hr" and "column_names" methods work together to allow you to have rows returned as hashrefs. You must call "column_names" first to declare your column names.
$csv->column_names (qw( code name price description ));
$hr = $csv->getline_hr ($io);
print "Price for $hr->{name} is $hr->{price} EUR\n";
"getline_hr" will croak if called before "column_names".
Note that "getline_hr" creates a hashref for every row and will be much slower than the combined use of "bind_columns" and "getline" but still offering the same ease of use hashref inside the loop:
my @cols = @{$csv->getline ($io)};
$csv->column_names (@cols);
while (my $row = $csv->getline_hr ($io)) {
print $row->{price};
}
Could easily be rewritten to the much faster:
my @cols = @{$csv->getline ($io)};
my $row = {};
$csv->bind_columns (\@{$row}{@cols});
while ($csv->getline ($io)) {
print $row->{price};
}
Your mileage may vary for the size of the data and the number of rows. With perl-5.14.2 the comparison for a 100_000 line file with 14 rows:
Rate hashrefs getlines
hashrefs 1.00/s -- -76%
getlines 4.15/s 313% --
getline_hr_all
$arrayref = $csv->getline_hr_all ($io);
$arrayref = $csv->getline_hr_all ($io, $offset);
$arrayref = $csv->getline_hr_all ($io, $offset, $length);
This will return a reference to a list of getline_hr ($io) results. In this call, keep_meta_info
is disabled.
parse
$status = $csv->parse ($line);
This method decomposes a CSV
string into fields, returning success or failure. Failure can result from a lack of argument or the given CSV
string is improperly formatted. Upon success, "fields" can be called to retrieve the decomposed fields. Upon failure calling "fields" will return undefined data and "error_input" can be called to retrieve the invalid argument.
You may use the "types" method for setting column types. See "types"' description below.
fragment
This function tries to implement RFC7111 (URI Fragment Identifiers for the text/csv Media Type) - http://tools.ietf.org/html/rfc7111
my $AoA = $csv->fragment ($io, $spec);
In specifications, *
is used to specify the last item, a dash (-
) to indicate a range. All indices are 1
-based: the first row or column has index 1
. Selections can be combined with the semi-colon (;
).
When using this method in combination with "column_names", the returned reference will point to a list of hashes instead of a list of lists. A disjointed cell-based combined selection might return rows with different number of columns making the use of hashes unpredictable.
$csv->column_names ("Name", "Age");
my $AoH = $csv->fragment ($io, "col=3;8");
If the "after_parse" callback is active, it is also called on every line parsed and skipped before the fragment.
- row
-
row=4 row=5-7 row=6-* row=1-2;4;6-*
- col
-
col=2 col=1-3 col=4-* col=1-2;4;7-*
- cell
-
In cell-based selection, the comma (
,
) is used to pair row and columncell=4,1
The range operator (
-
) usingcell
s can be used to define top-left and bottom-rightcell
locationcell=3,1-4,6
The
*
is only allowed in the second part of a paircell=3,2-*,2 # row 3 till end, only column 2 cell=3,2-3,* # column 2 till end, only row 3 cell=3,2-*,* # strip row 1 and 2, and column 1
Cells and cell ranges may be combined with
;
, possibly resulting in rows with different number of columnscell=1,1-2,2;3,3-4,4;1,4;4,1
Disjointed selections will only return selected cells. The cells that are not specified will not be included in the returned set, not even as
undef
. As an example given aCSV
like11,12,13,...19 21,22,...28,29 : : 91,...97,98,99
with
cell=1,1-2,2;3,3-4,4;1,4;4,1
will return:11,12,14 21,22 33,34 41,43,44
Overlapping cell-specs will return those cells only once, So
cell=1,1-3,3;2,2-4,4;2,3;4,2
will return:11,12,13 21,22,23,24 31,32,33,34 42,43,44
RFC7111 does not allow different types of specs to be combined (either row
or col
or cell
). Passing an invalid fragment specification will croak and set error 2013.
column_names
Set the "keys" that will be used in the "getline_hr" calls. If no keys (column names) are passed, it will return the current setting as a list.
"column_names" accepts a list of scalars (the column names) or a single array_ref, so you can pass the return value from "getline" too:
$csv->column_names ($csv->getline ($io));
"column_names" does no checking on duplicates at all, which might lead to unexpected results. Undefined entries will be replaced with the string "\cAUNDEF\cA"
, so
$csv->column_names (undef, "", "name", "name");
$hr = $csv->getline_hr ($io);
Will set $hr->{"\cAUNDEF\cA"}
to the 1st field, $hr->{""}
to the 2nd field, and $hr->{name}
to the 4th field, discarding the 3rd field.
"column_names" croaks on invalid arguments.
bind_columns
Takes a list of scalar references to be used for output with "print" or to store in the fields fetched by "getline". When you do not pass enough references to store the fetched fields in, "getline" will fail with error 3006
. If you pass more than there are fields to return, the content of the remaining references is left untouched.
$csv->bind_columns (\$code, \$name, \$price, \$description);
while ($csv->getline ($io)) {
print "The price of a $name is \x{20ac} $price\n";
}
To reset or clear all column binding, call "bind_columns" with the single argument undef
. This will also clear column names.
$csv->bind_columns (undef);
If no arguments are passed at all, "bind_columns" will return the list of current bindings or undef
if no binds are active.
eof
$eof = $csv->eof ();
If "parse" or "getline" was used with an IO stream, this method will return true (1) if the last call hit end of file, otherwise it will return false (''). This is useful to see the difference between a failure and end of file.
types
$csv->types (\@tref);
This method is used to force that (all) columns are of a given type. For example, if you have an integer column, two columns with doubles and a string column, then you might do a
$csv->types ([Text::CSV_XS::IV (),
Text::CSV_XS::NV (),
Text::CSV_XS::NV (),
Text::CSV_XS::PV ()]);
Column types are used only for decoding columns while parsing, in other words by the "parse" and "getline" methods.
You can unset column types by doing a
$csv->types (undef);
or fetch the current type settings with
$types = $csv->types ();
- IV
-
Set field type to integer.
- NV
-
Set field type to numeric/float.
- PV
-
Set field type to string.
fields
@columns = $csv->fields ();
This method returns the input to "combine" or the resultant decomposed fields of a successful "parse", whichever was called more recently.
Note that the return value is undefined after using "getline", which does not fill the data structures returned by "parse".
meta_info
@flags = $csv->meta_info ();
This method returns the "flags" of the input to "combine" or the flags of the resultant decomposed fields of "parse", whichever was called more recently.
For each field, a meta_info field will hold flags that inform something about the field returned by the "fields" method or passed to the "combine" method. The flags are bit-wise-or
'd like:
See the is_***
methods below.
is_quoted
my $quoted = $csv->is_quoted ($column_idx);
Where $column_idx
is the (zero-based) index of the column in the last result of "parse".
This returns a true value if the data in the indicated column was enclosed in quote_char
quotes. This might be important for fields where content ,20070108,
is to be treated as a numeric value, and where ,"20070108",
is explicitly marked as character string data.
This method is only valid when "keep_meta_info" is set to a true value.
is_binary
my $binary = $csv->is_binary ($column_idx);
Where $column_idx
is the (zero-based) index of the column in the last result of "parse".
This returns a true value if the data in the indicated column contained any byte in the range [\x00-\x08,\x10-\x1F,\x7F-\xFF]
.
This method is only valid when "keep_meta_info" is set to a true value.
is_missing
my $missing = $csv->is_missing ($column_idx);
Where $column_idx
is the (zero-based) index of the column in the last result of "getline_hr".
$csv->keep_meta_info (1);
while (my $hr = $csv->getline_hr ($fh)) {
$csv->is_missing (0) and next; # This was an empty line
}
When using "getline_hr", it is impossible to tell if the parsed fields are undef
because they where not filled in the CSV
stream or because they were not read at all, as all the fields defined by "column_names" are set in the hash-ref. If you still need to know if all fields in each row are provided, you should enable keep_meta_info
so you can check the flags.
status
$status = $csv->status ();
This method returns the status of the last invoked "combine" or "parse" call. Status is success (true: 1
) or failure (false: undef
or 0
).
error_input
$bad_argument = $csv->error_input ();
This method returns the erroneous argument (if it exists) of "combine" or "parse", whichever was called more recently. If the last invocation was successful, error_input
will return undef
.
error_diag
Text::CSV_XS->error_diag ();
$csv->error_diag ();
$error_code = 0 + $csv->error_diag ();
$error_str = "" . $csv->error_diag ();
($cde, $str, $pos, $rec, $fld) = $csv->error_diag ();
If (and only if) an error occurred, this function returns the diagnostics of that error.
If called in void context, this will print the internal error code and the associated error message to STDERR.
If called in list context, this will return the error code and the error message in that order. If the last error was from parsing, the rest of the values returned are a best guess at the location within the line that was being parsed. Their values are 1-based. The position currently is index of the byte at which the parsing failed in the current record. It might change to be the index of the current character in a later release. The records is the index of the record parsed by the csv instance. The field number is the index of the field the parser thinks it is currently trying to parse. See examples/csv-check for how this can be used.
If called in scalar context, it will return the diagnostics in a single scalar, a-la $!
. It will contain the error code in numeric context, and the diagnostics message in string context.
When called as a class method or a direct function call, the diagnostics are that of the last "new" call.
record_number
$recno = $csv->record_number ();
Returns the records parsed by this csv instance. This value should be more accurate than $.
when embedded newlines come in play. Records written by this instance are not counted.
SetDiag
$csv->SetDiag (0);
Use to reset the diagnostics if you are dealing with errors.
FUNCTIONS
csv
This function is not exported by default and should be explicitly requested:
use Text::CSV_XS qw( csv );
This is the second draft. This function will stay, but the arguments might change based on user feedback.
This is an high-level function that aims at simple (user) interfaces. This can be used to read/parse a CSV
file or stream (the default behavior) or to produce a file or write to a stream (define the out
attribute). It returns an array- or hash-reference on parsing (or undef
on fail) or the numeric value of "error_diag" on writing. When this function fails you can get to the error using the class call to "error_diag"
my $aoa = csv (in => "test.csv") or
die Text::CSV_XS->error_diag;
This function takes the arguments as key-value pairs. This can be passed as a list or as an anonymous hash:
my $aoa = csv ( in => "test.csv", sep_char => ";");
my $aoh = csv ({ in => $fh, headers => "auto" });
The arguments passed consist of two parts: the arguments to "csv" itself and the optional attributes to the CSV
object used inside the function as enumerated and explained in "new".
If not overridden, the default option used for CSV is
auto_diag => 1
The option that is always set and cannot be altered is
binary => 1
As this function will likely be used in one-liners, it allows quote
to be abbreviated as quo
, and escape_char
to be abbreviated as esc
or escape
.
Alternative invocations:
my $aoa = Text::CSV_XS::csv (in => "file.csv");
my $csv = Text::CSV_XS->new ();
my $aoa = $csv->csv (in => "file.csv");
In the latter case, the object attributes are used from the existing object and the attribute arguments in the function call are ignored:
my $csv = Text::CSV_XS->new ({ sep_char => ";" });
my $aoa = $csv->csv (in => "file.csv", sep_char => ",");
will parse using ;
as sep_char
, not ,
.
in
Used to specify the source. in
can be a file name (e.g. "file.csv"
), which will be opened for reading and closed when finished, a file handle (e.g. $fh
or FH
), a reference to a glob (e.g. \*ARGV
), the glob itself (e.g. *STDIN
), or a reference to a scalar (e.g. \q{1,2,"csv"}
).
When used with "out", in
should be a reference to a CSV structure (AoA or AoH) or a CODE-ref that returns an array-reference or a hash-reference. The code-ref will be invoked with no arguments.
my $aoa = csv (in => "file.csv");
open my $fh, "<", "file.csv";
my $aoa = csv (in => $fh);
my $csv = [ [qw( Foo Bar )], [ 1, 2 ], [ 2, 3 ]];
my $err = csv (in => $csv, out => "file.csv");
If called in void context without the "out" attribute, the resulting ref will be used as input to a subsequent call to csv:
csv (in => "file.csv", filter => { 2 => sub { length > 2 }})
will be a shortcut to
csv (in => csv (in => "file.csv", filter => { 2 => sub { length > 2 }}))
where, in the absence of the out
attribute, this is a shortcut to
csv (in => csv (in => "file.csv", filter => { 2 => sub { length > 2 }}),
out => *STDOUT)
out
In output mode, the default CSV options when producing CSV are
eol => "\r\n"
The "fragment" attribute is ignored in output mode.
out
can be a file name (e.g. "file.csv"
), which will be opened for writing and closed when finished, a file handle (e.g. $fh
or FH
), a reference to a glob (e.g. \*STDOUT
), or the glob itself (e.g. *STDOUT
).
csv (in => sub { $sth->fetch }, out => "dump.csv");
csv (in => sub { $sth->fetchrow_hashref }, out => "dump.csv",
headers => $sth->{NAME_lc});
When a code-ref is used for in
, the output is generated per invocation, so no buffering is involved. This implies that there is no size restriction on the number of records. The csv
function ends when the coderef returns a false value.
encoding
If passed, it should be an encoding accepted by the :encoding()
option to open
. There is no default value. This attribute does not work in perl 5.6.x. encoding
can be abbreviated to enc
for ease of use in command line invocations.
headers
If this attribute is not given, the default behavior is to produce an array of arrays.
If headers
is supplied, it should be either an anonymous list of column names, an anonymous hashref or a flag: auto
or skip
. When skip
is used, the header will not be included in the output.
my $aoa = csv (in => $fh, headers => "skip");
If auto
is used, the first line of the CSV
source will be read as the list of field headers and used to produce an array of hashes.
my $aoh = csv (in => $fh, headers => "auto");
If headers
is an anonymous list, the entries in the list will be used instead
my $aoh = csv (in => $fh, headers => [qw( Foo Bar )]);
csv (in => $aoa, out => $fh, headers => [qw( code description price }]);
If headers
is an hash reference, this implies auto
, but header fields for that exist as key in the hashref will be replaced by the value for that key. Given a CSV file like
post-kode,city,name,id number,fubble
1234AA,Duckstad,Donald,13,"X313DF"
using
csv (headers => { "post-kode" => "pc", "id number" => "ID" }, ...
will return an entry like
{ pc => "1234AA",
city => "Duckstad",
name => "Donald",
ID => "13",
fubble => "X313DF",
}
key
If passed, will default headers
to "auto"
and return a hashref instead of an array of hashes.
my $ref = csv (in => "test.csv", key => "code");
with test.csv like
code,product,price,color
1,pc,850,gray
2,keyboard,12,white
3,mouse,5,black
will return
{ 1 => {
code => 1,
color => 'gray',
price => 850,
product => 'pc'
},
2 => {
code => 2,
color => 'white',
price => 12,
product => 'keyboard'
},
3 => {
code => 3,
color => 'black',
price => 5,
product => 'mouse'
}
}
fragment
Only output the fragment as defined in the "fragment" method. This option is ignored when generating CSV
. See "out".
Combining all of them could give something like
use Text::CSV_XS qw( csv );
my $aoh = csv (
in => "test.txt",
encoding => "utf-8",
headers => "auto",
sep_char => "|",
fragment => "row=3;6-9;15-*",
);
say $aoh->[15]{Foo};
Callbacks
Callbacks enable actions triggered from the inside of Text::CSV_XS.
While most of what this enables can easily be done in an unrolled loop as described in the "SYNOPSIS" callbacks can be used to meet special demands or enhance the "csv" function.
- error
-
$csv->callbacks (error => sub { $csv->SetDiag (0) });
the
error
callback is invoked when an error occurs, but only when "auto_diag" is set to a true value. A callback is invoked with the values returned by "error_diag":my ($c, $s); sub ignore3006 { my ($err, $msg, $pos, $recno, $fldno) = @_; if ($err == 3006) { # ignore this error ($c, $s) = (undef, undef); Text::CSV_XS->SetDiag (0); } # Any other error return; } # ignore3006 $csv->callbacks (error => \&ignore3006); $csv->bind_columns (\$c, \$s); while ($csv->getline ($fh)) { # Error 3006 will not stop the loop }
- after_parse
-
$csv->callbacks (after_parse => sub { push @{$_[1]}, "NEW" }); while (my $row = $csv->getline ($fh)) { $row->[-1] eq "NEW"; }
This callback is invoked after parsing with "getline" only if no error occurred. The callback is invoked with two arguments: the current
CSV
parser object and an array reference to the fields parsed.The return code of the callback is ignored unless it is a reference to the string "skip", in which case the record will be skipped in "getline_all".
sub add_from_db { my ($csv, $row) = @_; $sth->execute ($row->[4]); push @$row, $sth->fetchrow_array; } # add_from_db my $aoa = csv (in => "file.csv", callbacks => { after_parse => \&add_from_db });
This hook can be used for validation:
- FAIL
-
Die if any of the records does not validate a rule:
after_parse => sub { $_[1][4] =~ m/^[0-9]{4}\s?[A-Z]{2}$/ or die "5th field does not have a valid Dutch zipcode"; }
- DEFAULT
-
Replace invalid fields with a default value:
after_parse => sub { $_[1][2] =~ m/^\d+$/ or $_[1][2] = 0 }
- SKIP
-
Skip records that have invalid fields (only applies to "getline_all"):
after_parse => sub { $_[1][0] =~ m/^\d+$/ or return \"skip"; }
- before_print
-
my $idx = 1; $csv->callbacks (before_print => sub { $_[1][0] = $idx++ }); $csv->print (*STDOUT, [ 0, $_ ]) for @members;
This callback is invoked before printing with "print" only if no error occurred. The callback is invoked with two arguments: the current
CSV
parser object and an array reference to the fields passed.The return code of the callback is ignored.
sub max_4_fields { my ($csv, $row) = @_; @$row > 4 and splice @$row, 4; } # max_4_fields csv (in => csv (in => "file.csv"), out => *STDOUT, callbacks => { before print => \&max_4_fields });
This callback is not active for "combine".
Callbacks for csv ()
The "csv" allows for some callbacks that do not integrate in XS internals but only feature the "csv" function.
csv (in => "file.csv",
callbacks => {
filter => { 6 => sub { $_ > 15 } }, # first
after_parse => sub { say "AFTER PARSE"; }, # first
after_in => sub { say "AFTER IN"; }, # second
on_in => sub { say "ON IN"; }, # third
},
);
csv (in => $aoh,
out => "file.csv",
callbacks => {
on_in => sub { say "ON IN"; }, # first
before_out => sub { say "BEFORE OUT"; }, # second
before_print => sub { say "BEFORE PRINT"; }, # third
},
);
- filter
-
This callback can be used to filter records. It is called just after a new record has been scanned. The callback accepts a hashref where the keys are the index to the row (the field number, 1-based) and the values are subs to return a true or false value.
csv (in => "file.csv", filter => { 3 => sub { m/a/ }, # third field should contain an "a" 5 => sub { length > 4 }, # length of the 5th field minimal 5 });
If the keys to the filter contain any character that in not a digit it will also implicitly set "headers" to
auto
unless "headers" was already passed as argument. When headers are active, returning an array of hashes, the filter is not applicable to the header itself.csv (in => "file.csv", filter => { foo => sub { $_ > 4 }});
All sub results should match, as in AND.
The context of the callback sets
$_
localized to the field indicated by the filter. The two arguments are as with all other callbacks, so the other fields in the current row can be seen:filter => { 3 => sub { $_ > 100 ? $_[1][1] =~ m/A/ : $_[1][6] =~ m/B/ }}
If the context is set to return a list of hashes ("headers" is defined), the current record will also be available in the localized
%_
:filter => { 3 => sub { $_ > 100 && $_{foo} =~ m/A/ && $_{bar} < 1000 }}
If the filter is used to alter the content by changing
$_
, make sure that the sub returns true in order not to have that record skipped:filter => { 2 => sub { $_ = uc }}
will upper-case the second field, and then skip it if the resulting content evaluates to false. To always accept, end with truth:
filter => { 2 => sub { $_ = uc; 1 }}
- after_in
-
This callback is invoked for each record after all records have been parsed but before returning the reference to the caller. The hook is invoked with two arguments: the current
CSV
parser object and a reference to the record. The reference can be a reference to a HASH or a reference to an ARRAY as determined by the arguments.This callback can also be passed as an attribute without the
callbacks
wrapper. - before_out
-
This callback is invoked for each record before the record is printed. The hook is invoked with two arguments: the current
CSV
parser object and a reference to the record. The reference can be a reference to a HASH or a reference to an ARRAY as determined by the arguments.This callback can also be passed as an attribute without the
callbacks
wrapper.This callback makes the row available in
%_
if the row is a hashref. In this case%_
is writable and will change the original row. - on_in
-
This callback acts exactly as the "after_in" or the "before_out" hooks.
This callback can also be passed as an attribute without the
callbacks
wrapper.This callback makes the row available in
%_
if the row is a hashref. In this case%_
is writable and will change the original row. So e.g. withmy $aoh = csv ( in => \"foo\n1\n2\n", headers => "auto", on_in => sub { $_{bar} = 2; }, );
$aoh
will be:[ { foo => 1, bar => 2, } { foo => 2, bar => 2, } ]
- csv
-
The function "csv" can also be called as a method or with an existing Text::CSV_XS object. This could help if the function is to be invoked a lot of times and the overhead of creating the object internally over and over again would be prevented by passing an existing instance.
my $csv = Text::CSV_XS->new ({ binary => 1, auto_diag => 1 }); my $aoa = $csv->csv (in => $fh); my $aoa = csv (in => $fh, csv => $csv);
both act the same. Running this 20000 times on a 20 lines CSV file, showed a 53% speedup.
INTERNALS
The arguments to these internal functions are deliberately not described or documented in order to enable the module authors make changes it when they feel the need for it. Using them is highly discouraged as the API may change in future releases.
EXAMPLES
Reading a CSV file line by line:
my $csv = Text::CSV_XS->new ({ binary => 1, auto_diag => 1 });
open my $fh, "<", "file.csv" or die "file.csv: $!";
while (my $row = $csv->getline ($fh)) {
# do something with @$row
}
close $fh or die "file.csv: $!";
Reading only a single column
my $csv = Text::CSV_XS->new ({ binary => 1, auto_diag => 1 });
open my $fh, "<", "file.csv" or die "file.csv: $!";
# get only the 4th column
my @column = map { $_->[3] } @{$csv->getline_all ($fh)};
close $fh or die "file.csv: $!";
with "csv", you could do
my @column = map { $_->[0] }
@{csv (in => "file.csv", fragment => "col=4")};
Parsing CSV strings:
my $csv = Text::CSV_XS->new ({ keep_meta_info => 1, binary => 1 });
my $sample_input_string =
qq{"I said, ""Hi!""",Yes,"",2.34,,"1.09","\x{20ac}",};
if ($csv->parse ($sample_input_string)) {
my @field = $csv->fields;
foreach my $col (0 .. $#field) {
my $quo = $csv->is_quoted ($col) ? $csv->{quote_char} : "";
printf "%2d: %s%s%s\n", $col, $quo, $field[$col], $quo;
}
}
else {
print STDERR "parse () failed on argument: ",
$csv->error_input, "\n";
$csv->error_diag ();
}
Printing CSV data
The fast way: using "print"
An example for creating CSV
files using the "print" method:
my $csv = Text::CSV_XS->new ({ binary => 1, eol => $/ });
open my $fh, ">", "foo.csv" or die "foo.csv: $!";
for (1 .. 10) {
$csv->print ($fh, [ $_, "$_" ]) or $csv->error_diag;
}
close $fh or die "$tbl.csv: $!";
The slow way: using "combine" and "string"
or using the slower "combine" and "string" methods:
my $csv = Text::CSV_XS->new;
open my $csv_fh, ">", "hello.csv" or die "hello.csv: $!";
my @sample_input_fields = (
'You said, "Hello!"', 5.67,
'"Surely"', '', '3.14159');
if ($csv->combine (@sample_input_fields)) {
print $csv_fh $csv->string, "\n";
}
else {
print "combine () failed on argument: ",
$csv->error_input, "\n";
}
close $csv_fh or die "hello.csv: $!";
Rewriting CSV
Rewrite CSV
files with ;
as separator character to well-formed CSV
:
use Text::CSV_XS qw( csv );
csv (in => csv (in => "bad.csv", sep_char => ";"), out => *STDOUT);
As STDOUT
is now default in "csv", a one-liner converting a UTF-16 CSV file with BOM and TAB-separation to valid UTF-8 CSV could be:
$ perl -C3 -MText::CSV_XS=csv -we\
'csv(in=>"utf16tab.csv",encoding=>"utf16",sep=>"\t")' >utf8.csv
Dumping database tables to CSV
Dumping a database table can be simple as this (TIMTOWTDI):
my $dbh = DBI->connect (...);
my $sql = "select * from foo";
# using your own loop
open my $fh, ">", "foo.csv" or die "foo.csv: $!\n";
my $csv = Text::CSV_XS->new ({ binary => 1, eol => "\r\n" });
my $sth = $dbh->prepare ($sql); $sth->execute;
$csv->print ($fh, $sth->{NAME_lc});
while (my $row = $sth->fetch) {
$csv->print ($fh, $row);
}
# using the csv function, all in memory
csv (out => "foo.csv", in => $dbh->selectall_arrayref ($sql));
# using the csv function, streaming with callbacks
my $sth = $dbh->prepare ($sql); $sth->execute;
csv (out => "foo.csv", in => sub { $sth->fetch });
csv (out => "foo.csv", in => sub { $sth->fetchrow_hashref });
Note that this does not discriminate between "empty" values and NULL-values from the database, as both will be the same empty field in CSV. To enable distinction between the two, use quote_empty
.
csv (out => "foo.csv", in => sub { $sth->fetch }, quote_empty => 1);
If the database import utility supports special sequences to insert NULL
values into the database, like MySQL/MariaDB supports \N
, use a filter or a map
csv (out => "foo.csv", in => sub { $sth->fetch },
on_in => sub { $_ //= "\\N" for @$_[1] });
while (my $row = $sth->fetch) {
$csv->print ($fh, [ map { $_ // "\\N" } @$row ]);
}
these special sequences are not recognized by Text::CSV_XS on parsing the CSV generated like this, but map and filter are your friends again
while (my $row = $csv->getline ($io)) {
$sth->execute (map { $_ eq "\\N" ? undef : $_ } @$row);
}
csv (in => "foo.csv", filter => { 1 => sub {
$sth->execute (map { $_ eq "\\N" ? undef : $_ } @{$_[1]}); 0; }});
The examples folder
For more extended examples, see the examples/ 1
. sub-directory in the original distribution or the git repository 2
.
1. https://github.com/Tux/Text-CSV_XS/tree/master/examples
2. https://github.com/Tux/Text-CSV_XS
The following files can be found there:
- parser-xs.pl
-
This can be used as a boilerplate to parse invalid
CSV
and parse beyond (expected) errors alternative to using the "error" callback.$ perl examples/parser-xs.pl bad.csv >good.csv
- csv-check
-
This is a command-line tool that uses parser-xs.pl techniques to check the
CSV
file and report on its content.$ csv-check files/utf8.csv Checked with examples/csv-check 1.5 using Text::CSV_XS 0.81 OK: rows: 1, columns: 2 sep = <,>, quo = <">, bin = <1>
- csv2xls
-
A script to convert
CSV
to Microsoft Excel. This requires Date::Calc and Spreadsheet::WriteExcel. The converter accepts various options and can produce UTF-8 Excel files. - csvdiff
-
A script that provides colorized diff on sorted CSV files, assuming first line is header and first field is the key. Output options include colorized ANSI escape codes or HTML.
$ csvdiff --html --output=diff.html file1.csv file2.csv
CAVEATS
Text::CSV_XS is not designed to detect the characters used to quote and separate fields. The parsing is done using predefined (default) settings. In the examples sub-directory, you can find scripts that demonstrate how you could try to detect these characters yourself.
Microsoft Excel
The import/export from Microsoft Excel is a risky task, according to the documentation in Text::CSV::Separator
. Microsoft uses the system's list separator defined in the regional settings, which happens to be a semicolon for Dutch, German and Spanish (and probably some others as well). For the English locale, the default is a comma. In Windows however, the user is free to choose a predefined locale, and then change every individual setting in it, so checking the locale is no solution.
As of version 1.17, a lone first line with just
sep=;
will be recognized and honored when parsing with "getline".
TODO
- More Errors & Warnings
-
New extensions ought to be clear and concise in reporting what error has occurred where and why, and maybe also offer a remedy to the problem.
"error_diag" is a (very) good start, but there is more work to be done in this area.
Basic calls should croak or warn on illegal parameters. Errors should be documented.
- setting meta info
-
Future extensions might include extending the "meta_info", "is_quoted", and "is_binary" to accept setting these flags for fields, so you can specify which fields are quoted in the "combine"/"string" combination.
$csv->meta_info (0, 1, 1, 3, 0, 0); $csv->is_quoted (3, 1);
Metadata Vocabulary for Tabular Data (a W3C editor's draft) could be an example for supporting more metadata.
- Parse the whole file at once
-
Implement new methods or functions that enable parsing of a complete file at once, returning a list of hashes. Possible extension to this could be to enable a column selection on the call:
my @AoH = $csv->parse_file ($filename, { cols => [ 1, 4..8, 12 ]});
Returning something like
[ { fields => [ 1, 2, "foo", 4.5, undef, "", 8 ], flags => [ ... ], }, { fields => [ ... ], . }, ]
Note that the "csv" function already supports most of this, but does not return flags. "getline_all" returns all rows for an open stream, but this will not return flags either. "fragment" can reduce the required rows or columns, but cannot combine them.
- Cookbook
-
Write a document that has recipes for most known non-standard (and maybe some standard)
CSV
formats, including formats that useTAB
,;
,|
, or other non-comma separators.Examples could be taken from W3C's CSV on the Web: Use Cases and Requirements
- Steal
- Perl6 support
-
I'm already working on perl6 support here. No promises yet on when it is finished (or fast). Trying to keep the API alike as much as possible.
NOT TODO
- combined methods
-
Requests for adding means (methods) that combine "combine" and "string" in a single call will not be honored (use "print" instead). Likewise for "parse" and "fields" (use "getline" instead), given the problems with embedded newlines.
Release plan
No guarantees, but this is what I had in mind some time ago:
DIAGNOSTICS section in pod to *describe* the errors (see below)
EBCDIC
The current hard-coding of characters and character ranges makes this code unusable on EBCDIC
systems. Recent work in perl-5.20 might change that.
Opening EBCDIC
encoded files on ASCII
+ systems is likely to succeed using Encode's cp37
, cp1047
, or posix-bc
:
open my $fh, "<:encoding(cp1047)", "ebcdic_file.csv" or die "...";
DIAGNOSTICS
Still under construction ...
If an error occurs, $csv->error_diag
can be used to get information on the cause of the failure. Note that for speed reasons the internal value is never cleared on success, so using the value returned by "error_diag" in normal cases - when no error occurred - may cause unexpected results.
If the constructor failed, the cause can be found using "error_diag" as a class method, like Text::CSV_XS->error_diag
.
The $csv->error_diag
method is automatically invoked upon error when the contractor was called with auto_diag
set to 1
or 2
, or when autodie is in effect. When set to 1
, this will cause a warn
with the error message, when set to 2
, it will die
. 2012 - EOF
is excluded from auto_diag
reports.
Errors can be (individually) caught using the "error" callback.
The errors as described below are available. I have tried to make the error itself explanatory enough, but more descriptions will be added. For most of these errors, the first three capitals describe the error category:
INI
Initialization error or option conflict.
ECR
Carriage-Return related parse error.
EOF
End-Of-File related parse error.
EIQ
Parse error inside quotation.
EIF
Parse error inside field.
ECB
Combine error.
EHR
HashRef parse related error.
And below should be the complete list of error codes that can be returned:
1001 "INI - sep_char is equal to quote_char or escape_char"
The separation character cannot be equal to the quotation character or to the escape character, as this would invalidate all parsing rules.
1002 "INI - allow_whitespace with escape_char or quote_char SP or TAB"
Using the
allow_whitespace
attribute when eitherquote_char
orescape_char
is equal toSPACE
orTAB
is too ambiguous to allow.1003 "INI - \r or \n in main attr not allowed"
Using default
eol
characters in eithersep_char
,quote_char
, orescape_char
is not allowed.1004 "INI - callbacks should be undef or a hashref"
The
callbacks
attribute only allows one to beundef
or a hash reference.1005 "INI - EOL too long"
The value passed for EOL is exceeding its maximum length (16).
1006 "INI - SEP too long"
The value passed for SEP is exceeding its maximum length (16).
1007 "INI - QUOTE too long"
The value passed for QUOTE is exceeding its maximum length (16).
2010 "ECR - QUO char inside quotes followed by CR not part of EOL"
When
eol
has been set to anything but the default, like"\r\t\n"
, and the"\r"
is following the second (closing)quote_char
, where the characters following the"\r"
do not make up theeol
sequence, this is an error.2011 "ECR - Characters after end of quoted field"
Sequences like
1,foo,"bar"baz,22,1
are not allowed."bar"
is a quoted field and after the closing double-quote, there should be either a new-line sequence or a separation character.2012 "EOF - End of data in parsing input stream"
Self-explaining. End-of-file while inside parsing a stream. Can happen only when reading from streams with "getline", as using "parse" is done on strings that are not required to have a trailing
eol
.2013 "INI - Specification error for fragments RFC7111"
Invalid specification for URI "fragment" specification.
2021 "EIQ - NL char inside quotes, binary off"
Sequences like
1,"foo\nbar",22,1
are allowed only when the binary option has been selected with the constructor.2022 "EIQ - CR char inside quotes, binary off"
Sequences like
1,"foo\rbar",22,1
are allowed only when the binary option has been selected with the constructor.2023 "EIQ - QUO character not allowed"
Sequences like
"foo "bar" baz",qu
and2023,",2008-04-05,"Foo, Bar",\n
will cause this error.2024 "EIQ - EOF cannot be escaped, not even inside quotes"
The escape character is not allowed as last character in an input stream.
2025 "EIQ - Loose unescaped escape"
An escape character should escape only characters that need escaping.
Allowing the escape for other characters is possible with the attribute "allow_loose_escape".
2026 "EIQ - Binary character inside quoted field, binary off"
Binary characters are not allowed by default. Exceptions are fields that contain valid UTF-8, that will automatically be upgraded if the content is valid UTF-8. Set
binary
to1
to accept binary data.2027 "EIQ - Quoted field not terminated"
When parsing a field that started with a quotation character, the field is expected to be closed with a quotation character. When the parsed line is exhausted before the quote is found, that field is not terminated.
2030 "EIF - NL char inside unquoted verbatim, binary off"
2031 "EIF - CR char is first char of field, not part of EOL"
2032 "EIF - CR char inside unquoted, not part of EOL"
2034 "EIF - Loose unescaped quote"
2035 "EIF - Escaped EOF in unquoted field"
2036 "EIF - ESC error"
2037 "EIF - Binary character in unquoted field, binary off"
2110 "ECB - Binary character in Combine, binary off"
2200 "EIO - print to IO failed. See errno"
3001 "EHR - Unsupported syntax for column_names ()"
3002 "EHR - getline_hr () called before column_names ()"
3003 "EHR - bind_columns () and column_names () fields count mismatch"
3004 "EHR - bind_columns () only accepts refs to scalars"
3006 "EHR - bind_columns () did not pass enough refs for parsed fields"
3007 "EHR - bind_columns needs refs to writable scalars"
3008 "EHR - unexpected error in bound fields"
3009 "EHR - print_hr () called before column_names ()"
3010 "EHR - print_hr () called with invalid arguments"
SEE ALSO
IO::File, IO::Handle, IO::Wrap, Text::CSV, Text::CSV_PP, Text::CSV::Encoded, Text::CSV::Separator, Text::CSV::Slurp, Spreadsheet::CSV and Spreadsheet::Read, and of course perl.
If you are using perl6, you can have a look at Text::CSV
in the perl6 ecosystem, offering the same features.
non-perl
A CSV parser in JavaScript, also used by W3C, is the multi-threaded in-browser PapaParse.
csvkit is a python CSV parsing toolkit.
AUTHOR
Alan Citterman <alan@mfgrtl.com> wrote the original Perl module. Please don't send mail concerning Text::CSV_XS to Alan, who is not involved in the C/XS part that is now the main part of the module.
Jochen Wiedmann <joe@ispsoft.de> rewrote the en- and decoding in C by implementing a simple finite-state machine. He added variable quote, escape and separator characters, the binary mode and the print and getline methods. See ChangeLog releases 0.10 through 0.23.
H.Merijn Brand <h.m.brand@xs4all.nl> cleaned up the code, added the field flags methods, wrote the major part of the test suite, completed the documentation, fixed most RT bugs, added all the allow flags and the "csv" function. See ChangeLog releases 0.25 and on.
COPYRIGHT AND LICENSE
Copyright (C) 2007-2016 H.Merijn Brand. All rights reserved.
Copyright (C) 1998-2001 Jochen Wiedmann. All rights reserved.
Copyright (C) 1997 Alan Citterman. All rights reserved.
This library is free software; you can redistribute and/or modify it under the same terms as Perl itself.