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SuperSplit - Provides methods to split/join in two or more dimensions


 use SuperSplit ; #or qw/!:all supersplit/ |which function you want to use
 #first example: split on newlines and whitespace and print
 #the same data joined on tabs and whitespace. The split works on STDIN
 print superjoin( supersplit() );  #behaves like while (<>) 
 #second: split a table in a text file, and join it to HTML
 my $array2D   = supersplit( \*INPUT )  #filehandle must be open
 my $htmltable = superjoin( '</TD><TD>', "</TD></TR>\n  <TR><TD>", 
                                 $array2D );
 $htmltable    = "<TABLE>\n  <TR><TD>" . $htmltable . 
 print $htmltable;
 #third: perl allows you to have varying number of columns in a row,
 # so don't stop with simple tables. To split a piece of text into 
 # paragraphs, than words, try this:
 undef $/;
 $_ = <>;
 tr/.!();:?/ /; #remove punctiation
 my $array = supersplit( '\s+', '\n\s*\n', $_ );
 # now you can do something nifty as counting the number of words in each
 # paragraph
 my $i = 0;
 for my $rowref (@$array) {
    print "Found ".@$rowref." \twords in paragraph \t".++$i."\n";
 #other uses:
 $a = supersplit( 2 );  #behaves like supersplit(), but stops with the 
second column
 $b = supersplit_open( "<$file", 2 ); #as before, but opens $file for 
 $c = supersplit_open( "<$file"); #as before, but splits as much as it can
 $d = supersplit_nolimit( 3); #Hopelessly tries to split on 3.
 $e = supersplit_limits( [ ], [2,2] ); #$a, but returns 2x2 array
 $f = supersplit_hashref( {     separators => [ ], limits => [2,2],
        filehandle => \*STDIN }); #as before, but using anonhash to determine 


Supersplit is just a consequence of the possibility to use multi-dimensional arrays in perl. Because that is possible, one also wants a way to convenienently split data into a nD-array (at least I want to). And vice versa, of course. Supersplit/join just do that.

Because I intend to use these methods in numerous one-liners and in my collection of handy filters, an object interface is more often than not cumbersome. So, this module exports six methods 'super...', but no variables or globs of any kind. If you think modules shouldn't export functions, period, use the object interface, SuperSplit::Obj. TIMTOWTDT

If you don't like input magic, you can use the hashref variant. It uses only little of that ;-).

supersplit( @separator-list, $filehandleref || $string, $limit);

The first method, supersplit, returns a nD-array. To do that, it needs data and the strings to split with. Data may be provided as a reference to a filehandle, or as a string. If you want use a string for the data, you MUST provide the strings to split with (>=3 argument mode). If you don't provide data, supersplit works on STDIN. If you provide a filehandle (like \*INPUT), supersplit doesn't need the splitting strings, and runs in 2D-mode by default. In both cases (STDIN or filehandle only) it assumes columns are separated by whitespace, and rows are separated by newlines. Strings are passed directly to split. If you provide more separators, they will split the higher dimensions. If you only provide one, it is treated like the column-separator, the row-separator defaults to newline.

The separators are processed in reversed order, the last separator is processed first. This is best explained with a simple whitespace delimited table:

1 -1 4.32 new

2 0 3.23 old

3 -1 10.11 old

The default separator list, ('\s+', '\n') first splits on newlines, resulting in three rows. Each row than is splitted on whitespace, resulting in four columns every row. The last element of the resulting array is found by $array->[2][3] (indici start at zero).

You may pass an optional last parameter that contains an integer only. This is passed to split as the LIMIT parameter. See "split" in perlfunc for more details, it just limits the number of times that split splits. The LIMIT paramter is only used in the last dimension (aka, first delimiter). In case your string can be an integer only (that means, no other characters present) and you have more than two dimensions, you should use supersplit_nolimit, or provide a bogus LIMIT like -1.

A final remark an this function: It first tries to interpret your input as a filehandle and than as a string. Maybe you don't want that, if you are using IO::Scalar for example. In that case, convert your object to a string before passing it.

Supersplit returns a multi-dimensional array or undef if an error occurred.


Behaves like supersplit, except that is does not try to interpret the last parameter as the LIMIT parameter for split.


Behaves like supersplit (including LIMIT behavior), except that it opens the input string with open( INPUT, "$string" ). If that fails, supersplit_open confesses, and it carps if INPUT turns out to be empty. See Carp for more details.

supersplit_limits( $fh || $string, $separator_arrayref, $limits_arrayref)

Behaves like supersplit, but the separator list must be provided as a reference to an array, just as the list with LIMITs. If the LIMIT list has less members than the separator list, the last dimensions will be called without LIMIT. Both the separators and limits are popped, that is the lists will be processed from right to left, just like the separator list in previously descrived methods.

This method can be used to parse tables that need a limit on a higher dimension, I understand the .csv format is an example of that.

supersplit_hashref( $hashref)

This is just a wrapper around supersplit_limits. All arguments are passed as members of the referenced hash. These members are: 'separators', 'limits', 'string', 'filehandle' and 'open'. The members 'separators' and 'limits' must be references to arrays. The method passed these references to supersplit_limits, see above for a description. On the other arguments, the method tries to get 'string' first, than the 'filehandle' and if that fails tries to use the 'open' member.

superjoin( $colseparator, $rowseparator, $array2D );

The fourth and last method, superjoin, takes a nD-array and returns it as a string. The default behavior assumes 2D-array. In the string, columns (adjacent cells) are separated by the first argument provided. Rows (normally lines) are separated by the second argument. Alternatively, you may give the 2D-array as the only argument. In that case, superjoin joins columns with a tab ("\t"), and rows with a newline ("\n"). If you have more dimensions in your array, all separators for all dimensions should be provided. If you don't, superjoin stops at the second-last dimension. Just as with supersplit, separators are processed in reversed order: the last separator/delimiter is processed first.

Superjoin returns an undef if an error occurred, for example if you give a ref to an hash. If your first dimension points to hashes or strings, superjoin will return undef. Mixed arrays will break the code.


Jeroen Elassaiss-Schaap, with great help from Ben Tilly, who rewrote most of the code for version 0.02.


Perl/ artisitic license