Changes for version 0.3214 - 2026-10-05
- read_table(): delimited text
- colClasses read past the end of a field the parser had not copied: Atof() ran on into the separator and the next field whenever the separator could continue a number, so with sep '.' the field "1" of "1.2" came back as 1.2, and with sep 'E' the "1" of "1E2" as 100. The number is now parsed from a copy of the field alone.
- A quoted first field starting with the comment marker lost it: a header written '"#a",b' came back as a column named a, and where the next row was text as well the header was dropped and that row taken in its place. A comment marker inside quotes is now text, as R's read.table reads it.
- A sep regex under Unicode rules -- /u, which `use v5.12` and later put on every qr//, or one using \p{} -- was matched against each line's bytes, and took the trailing 0xA0 or 0x85 byte of a UTF-8 character for a no-break space or NEL: qr/\s+/u cut "voilà" into "voil\xC3" and a separator, and Cyrillic "Р" likewise, and never split on a U+2003. A valid UTF-8 line is now matched as UTF-8 by such a pattern, and by one under /a; a Latin-1 line is matched as bytes, as before, and the fields are the file's bytes either way.
- A read error was reported with libc's strerror() of whatever errno held, which on a threaded perl is not the function $! calls, and which could be stale. The reason now comes from $!, and only when the failing read set one.
- read_table(): Excel workbooks
- A phonetic guide (<rPh>) is no longer read as part of the text. Japanese Excel records the furigana for every string typed through the input method, and 漢字 read back as 漢字カンジ.
- The shared-string table is found through the workbook's relationships instead of by its usual name. A workbook that stored it as xl/SharedStrings.xml read every string cell as empty, and the first data row silently became the header.
- .xlsm, .xltx and .xltm files are read as workbooks. They were read as text and reported as an alignment error.
- Attributes quoted with ' are read, as XML allows; a workbook written that way lost every sheet name and its sheets were matched by position. A sheet with no name no longer takes the key of a sheet really called SheetN.
- The XML is read as an XML parser reads it: a commented-out row is not data, a CDATA section is its literal text, and a CR LF or lone CR in a cell is LF ( is still a CR). A character reference to something XML does not allow (�, a surrogate, anything past U+10FFFF) is left in the text, where it used to come back as bytes that are not UTF-8; and one to a noncharacter such as  no longer dies on perls before 5.14.
- Excel's _xHHHH_ escape for a character XML cannot hold (_x0000_ for NUL, _x005F_ for a literal underscore) is decoded in string cells, as Excel and LibreOffice decode it, so a cell with a control character in it reads back as itself; a formula's cached result is left as written.
- An .xlsx read as an aoh leaked a row hash when colClasses refused a cell. Every cell is now converted before the row's hash is made.
- read_table(): speed and memory
- The parser tests each field against na_strings as it cuts it, so an NA cell never gets a string buffer and the rows need no second pass. A 300,000 x 10 CSV with half its cells "." reads 25-30% faster (aoa 0.218 s to 0.153 s, aoh 0.285 s to 0.215 s, hoa 0.208 s to 0.147 s); one with no NA cells, 3-6% faster.
- sep => qr/\s+/ is split in C rather than by a regex match per field, with the same rows, errors and warnings. A 300,000 x 10 whitespace- separated file reads as an aoa in 0.18 s rather than 0.35 s, and as an aoh in 0.24 s rather than 0.41 s.
- An .xlsx's shared strings are kept once and shared by every cell that uses them: a 500,000-row sheet of categorical columns takes 188 MB instead of 249 MB, and reads 7% faster. On perls before 5.18 such a cell reports itself read-only to Scalar::Util::readonly, though assigning to it works as before.
- write_table(): records read_table could not see
- A record whose only field was empty, undef or blank was written as a blank line, which read_table skips, so a one-column table lost those rows and every later row moved up. It is now written quoted, '""' or '" "', as csv.writer writes [''] (CPython 3.14.2 test_csv.py). A first field starting with '#' is quoted too, since read_table took the record for a comment.
- An undef in an AoA's col_names was skipped, so every later name moved one column left: ['a', undef, 'c'] over [1, 2, 3] wrote "a,c,". It is now an empty header cell in its place. A reference in a header cell is refused as one in a data cell is, where it was written as its address.
- write_table(): arguments
- sep => '', and a sep holding a NUL, a quote, a CR or a LF, are refused, as is a file name holding a NUL, which used to be cut short there.
- row_names => 'name' now heads an AoA's or a flat hash's 1..n label column, as it heads a HoH's, where it was ignored. A HoA row_names that names no column dies, and AoH rows without it draw one warning with their count, where both gave empty labels silently.
- Rows that are restricted hashes missing a column no longer die with "Attempt to access disallowed key".
- write_table(): .xlsx workbooks Excel and openpyxl can open
- U+FFFE, U+FFFF and surrogates were written raw, and openpyxl refused the workbook as not well-formed. They, and the control characters that used to be dropped, are now written as Excel's _xHHHH_ escape, as XlsxWriter writes them. Every underscore that would open an escape is itself escaped as _x005F_, overlapping ones included, where XlsxWriter escapes only non-overlapping matches and a literal "_x005F_x0041_" came back from a left-to-right decoder as "_x005FA".
- Excel's limits are enforced: 16384 columns, 1048576 rows with the header, 32767 characters in a cell. A 16385th column used to be written as XFE. xlsx_freeze_rows and xlsx_freeze_cols are bounded, where 2**32 + 1 froze one row.
- A string becomes a number cell only when Excel would show it as it stands, so "007", "+5" and 20-digit IDs stay text, and "1e400" is no longer an infinite number. A value perl holds as a number is always a number cell, except Inf and NaN.
- write_table(): LaTeX
- Every line of tex_comment is now a comment: a newline in it used to end the comment, and the rest was typeset. An object passed as tex_comment or xlsx_comment is stringified rather than dropped.
- '<' becomes \textless{}, as '>' became \textgreater{}; it printed as an inverted exclamation mark. \ $ { } ^ ~ stay raw so cells can hold math and macros, and the documentation now says so.
- A croak after the .tex file was opened no longer leaves its handle open.
- write_table(): speed and memory
- Finding an AoH's or a HoH's columns no longer leaves an iterator on every row hash: 200,000 rows came back 22.9 MB heavier. The AoH write is 16% faster (0.342 s to 0.288 s) and the HoH write 13% faster (0.806 s to 0.704 s), and an AoH written as .xlsx peaks 0.7 MB over its data rather than 30 MB.
Modules
Get basic statistical functions, like in R, but with Perl using XS for performance