Provided by: libtext-table-perl_1.123-1_amd64 
NAME
Text::Table - Organize Data in Tables
SYNOPSIS
use Text::Table;
my $tb = Text::Table->new(
"Planet", "Radius\nkm", "Density\ng/cm^3"
);
$tb->load(
[ "Mercury", 2360, 3.7 ],
[ "Venus", 6110, 5.1 ],
[ "Earth", 6378, 5.52 ],
[ "Jupiter", 71030, 1.3 ],
);
print $tb;
This prints a table from the given title and data like this:
Planet Radius Density
km g/cm^3
Mercury 2360 3.7
Venus 6110 5.1
Earth 6378 5.52
Jupiter 71030 1.3
Note that two-line titles work, and that the planet names are aligned differently than the numbers.
DESCRIPTION
Organization of data in table form is a time-honored and useful method of data representation. While
columns of data are trivially generated by computer through formatted output, even simple tasks like
keeping titles aligned with the data columns are not trivial, and the one-shot solutions one comes up
with tend to be particularly hard to maintain. Text::Table allows you to create and maintain tables that
adapt to alignment requirements as you use them.
Overview
The process is simple: you create a table (a Text::Table object) by describing the columns the table is
going to have. Then you load lines of data into the table, and finally print the resulting output lines.
Alignment of data and column titles is handled dynamically in dependence on the data present.
Table Creation
In the simplest case, if all you want is a number of (untitled) columns, you create an unspecified table
and start adding data to it. The number of columns is taken fronm the first line of data.
To specify a table you specify its columns. A column description can contain a title and alignment
requirements for the data, both optional. Additionally, you can specify how the title is aligned with
the body of a column, and how the lines of a multiline title are aligned among themselves.
The columns are collected in the table in the order they are given. On data entry, each column
corresponds to one data item, and in column selection columns are indexed left to right, starting from 0.
Each title can be a multiline string which will be blank-filled to the length of the longest partial
line. The largest number of title lines in a column determines how many title lines the table has as a
whole, including the case that no column has any titles.
On output, Columns are separated by a single blank. You can control what goes between columns by
specifying separators between (or before, or after) columns. Separators don't contain any data and don't
count in column indexing. They also don't accumulate: in a sequence of only separators and no columns,
only the last one counts.
Status Information
The width (in characters), height (in lines), number of columns, and similar data about the table is
available.
Data Loading
Table data is entered line-wise, each time specifying data entries for all table columns. A bulk loader
for many lines at once is also available. You can clear the data from the table for re-use (though you
will more likely just create another table).
Data can contain colorizing escape sequences (as provided by "Term::AnsiColor") without upsetting the
alignment.
Table Output
The output area of a table is divided in the title and the body.
The title contains the combined titles from the table columns, if any. Its content never changes with a
given table, but it may be spread out differently on the page through alignment with the data.
The body contains the data lines, aligned column-wise as specified, and left-aligned with the column
title.
Each of these is arranged like a Perl array (counting from 0) and can be accessed in portions by
specifying a first line and the number of following lines. Also like an array, giving a negative first
line counts from the end of the area. The whole table, the title followed by the body, can also be
accessed in this manner.
The subdivisions are there so you can repeat the title (or parts of it) along with parts of the body on
output, whether for screen paging or printout.
A rule line is also available, which is the horizontal counterpart to the separator columns you specify
with the table. It is basically a table line as it would appear if all data entries in the line were
empty, that is, a blank line except for where the column separators have non-blank entries. If you print
it between data lines, it will not disrupt the vertical separator structure as a plain blank line would.
You can also request a solid rule consisting of any character, and even one with the non-blank column
separators replaced by a character of your choice. This way you can get the popular representation of
line-crossings like so:
|
----+---
|
Warning Control
On table creation, some parameters are checked and warnings issued if you allow warnings. You can also
turn warnings into fatal errors.
SPECIFICATIONS
Column Specification
Each column specification is a single scalar. Columns can be either proper data columns or column
separators. Both can be specified either as (possibly multi-line) strings, or in a more explicit form as
hash-refs. In the string form, proper columns are given as plain strings, and separators are given as
scalar references to strings. In hash form, separators have a true value in the field "is_sep" while
proper columns don't have this field.
Columns as strings
A column is given as a column title (any number of lines), optionally followed by alignment
requirements. Alignment requirements start with a line that begins with an ampersamd "&". However,
only the last such line counts as such, so if you have title lines that begin with "&", just append
an ampersand on a line by itself as a dummy alignment section if you don't have one anyway.
What follows the ampersand on its line is the alignment style (like left, right, ... as described in
"Alignment"), you want for the data in this column. If nothing follows, the general default auto is
used. If you specify an invalid alignment style, it falls back to left alignment.
The lines that follow can contain sample data for this column. These are considered for alignment in
the column, but never actually appear in the output. The effect is to guarantee a minimum width for
the column even if the current data doesn't require it. This helps dampen the oscillations in the
appearance of dynamically aligned tables.
Columns as Hashes
The format is
{
title => $title,
align => $align,
sample => $sample,
align_title => $align_title,
align_title_lines => $align_title_lines,
}
$title contains the title lines and $sample the sample data. Both can be given as a string or as an
array-ref to the list of lines. $align contains the alignment style (without a leading ampersand),
usually as a string. You can also give a regular expression here, which specifies regex alignment.
A regex can only be specified in the hash form of a colunm specification.
In hash form you can also specify how the title of a column is aligned with its body. To do this,
you specify the keyword "align_title" with "left", "right" or "center". Other alignment
specifications are not valid here. The default is "left".
"align_title" also specifies how the lines of a multiline title are aligned among themselves. If you
want a different alignment, you can specify it with the key "align_title_lines". Again, only "left",
"right" or "center" are allowed.
Do not put other keys than those mentioned above (title, align, align_title, align_title_lines, and
sample) into a hash that specifies a column. Most would be ignored, but some would confuse the
interpreter (in particular, is_sep has to be avoided).
Separators as strings
A separator must be given as a reference to a string (often a literal, like "\' | '"), any string
that is given directly describes a column.
It is usually just a (short) string that will be printed between table columns on all table lines
instead of the default single blank. If you specify two separators (on two lines), the first one
will be used in the title and the other in the body of the table.
Separators as Hashes
The hash representation of a separator has the format
{
is_sep => 1,
title => $title,
body => $body,
}
$title is the separator to be used in the title area and $body the one for the body. If only one is
given, the other is used for both. If none is given, a blank is used. If one is shorter than the
other, it is blank filled on the right.
The value of "is_sep" must be set to a true value, this is the distinguishing feature of a separator.
Alignment
The original documentation to Text::Aligner contains all the details on alignment specification, but here
is the rundown:
The possible alignment specifications are left, right, center, num and point (which are synonyms), and
auto. The first three explain themselves.
num (and point) align the decimal point in the data, which is assumed to the right if none is present.
Strings that aren't numbers are treated the same way, that is, they appear aligned with the integers
unless they contain a ".". Instead of the decimal point ".", you can also specify any other string in
the form num(,), for instance. The string in parentheses is aligned in the data. The synonym point for
num may be more appropriate in contexts that deal with arbitrary strings, as in point(=>) (which might be
used to align certain bits of Perl code).
regex alignment is a more sophisticated form of point alignment. If you specify a regular expression, as
delivered by "qr//", the start of the match is used as the alignment point. If the regex contains
capturing parentheses, the last submatch counts. [The usefulness of this feature is under
consideration.]
auto alignment combines numeric alignment with left alignment. Data items that look like numbers, and
those that don't, form two virtual columns and are aligned accordingly: "num" for numbers and "left" for
other strings. These columns are left-aligned with each other (i.e. the narrower one is blank-filled) to
form the final alignment.
This way, a column that happens to have only numbers in the data gets num alignment, a column with no
numbers appears left-aligned, and mixed data is presented in a reasonable way.
Column Selection
Besides creating tables from scratch, they can be created by selecting columns from an existing table.
Tables created this way contain the data from the columns they were built from.
This is done by specifying the columns to select by their index (where negative indices count backward
from the last column). The same column can be selected more than once and the sequence of columns can be
arbitrarily changed. Separators don't travel with columns, but can be specified between the columns at
selection time.
You can make the selection of one or more columns dependent on the data content of one of them. If you
specify some of the columns in angle brackets [...], the whole group is only included in the selection if
the first column in the group contains any data that evaluates to boolean true. That way you can de-
select parts of a table if it contains no interesting data. Any column separators given in brackets are
selected or deselected along with the rest of it.
PUBLIC METHODS
Table Creation
new()
my $tb = Text::Table->new( $column, ... );
creates a table with the columns specified. A column can be proper column which contains and
displays data, or a separator which tells how to fill the space between columns. The format of the
parameters is described under "Column Specification". Specifying an invalid alignment for a column
results in a warning if these are allowed.
If no columns are specified, the number of columns is taken from the first line of data added to the
table. The effect is as if you had specified "Text::Table->new( ( '') x $n)", where $n is the number
of columns.
select()
my $sub = $tb->select( $column, ...);
creates a table from the listed columns of the table $tb, including the data. Columns are specified
as integer indices which refer to the data columns of $tb. Columns can be repeated and specified in
any order. Negative indices count from the last column. If an invalid index is specified, a warning
is issued, if allowed.
As with "new()", separators can be interspersed among the column indices and will be used between the
columns of the new table.
If you enclose some of the arguments (column indices or separators) in angle brackets "[...]"
(technically, you specify them inside an arrayref), they form a group for conditional selection. The
group is only included in the resulting table if the first actual column inside the group contains
any data that evaluate to a boolean true. This way you can exclude groups of columns that wouldn't
contribute anything interesting. Note that separators are selected and de-selected with their group.
That way, more than one separator can appear between adjacent columns. They don't add up, but only
the rightmost separator is used. A group that contains only separators is never selected. [Another
feature whose usefulness is under consideration.]
Status Information
n_cols()
$tb->n_cols
returns the number of columns in the table.
width()
$tb->width
returns the width (in characters) of the table. All table lines have this length (not counting a
final "\n" in the line), as well as the separator lines returned by $tb->rule() and $b->body_rule().
The width of a table can potentially be influenced by any data item in it.
height()
$tb->height
returns the total number of lines in a table, including title lines and body lines. For
orthogonality, the synonym table_height() also exists.
table_height()
Same as "$table->height()".
title_height()
$tb->title_height
returns the number of title lines in a table.
body_height()
$tb->body_height
returns the number of lines in the table body.
colrange()
$tb->colrange( $i)
returns the start position and width of the $i-th column (counting from 0) of the table. If $i is
negative, counts from the end of the table. If $i is larger than the greatest column index, an
imaginary column of width 0 is assumed right of the table.
Data Loading
add()
$tb->add( $col1, ..., $colN)
adds a data line to the table, returns the table.
$col1, ..., $colN are scalars that correspond to the table columns. Undefined entries are converted
to '', and extra data beyond the number of table columns is ignored.
Data entries can be multi-line strings. The partial strings all go into the same column. The
corresponding fields of other columns remain empty unless there is another multi-line entry in that
column that fills the fieds. Adding a line with multi-line entries is equivalent to adding multiple
lines.
Every call to "add()" increases the body height of the table by the number of effective lines, one in
the absence of multiline entries.
load()
$tb->load( $line, ...)
loads the data lines given into the table, returns the table.
Every argument to "load()" represents a data line to be added to the table. The line can be given as
an array(ref) containing the data items, or as a string, which is split on whitespace to retrieve the
data. If an undefined argument is given, it is treated as an empty line.
clear()
$tb->clear;
deletes all data from the table and resets it to the state after creation. Returns the table. The
body height of a table is 0 after "clear()".
Table Output
The three methods "table()", "title()", and "body()" are very similar. They access different parts of
the printable output lines of a table with similar methods. The details are described with the "table()"
method.
table()
The "table()" method returns lines from the entire table, starting with the first title line and
ending with the last body line.
In array context, the lines are returned separately, in scalar context they are joined together in a
single string.
my @lines = $tb->table;
my $line = $tb->table( $line_number);
my @lines = $tb->table( $line_number, $n);
The first call returns all the lines in the table. The second call returns one line given by
$line_number. The third call returns $n lines, starting with $line_number. If $line_number is
negative, it counts from the end of the array. Unlike the "select()" method, "table()" (and its
sister methods "title()" and "body()") is protected against large negative line numbers, it truncates
the range described by $line_number and $n to the existing lines. If $n is 0 or negative, no lines
are returned (an empty string in scalar context).
stringify()
Returns a string representation of the table. This method is called for stringification by overload.
my @table_strings = map { $_->stringify() } @tables;
title()
Returns lines from the title area of a table, where the column titles are rendered. Parameters and
response to context are as with "table()", but no lines are returned from outside the title area.
body()
Returns lines from the body area of a table, that is the part where the data content is rendered, so
that $tb->body( 0) is the first data line. Parameters and response to context are as with "table()".
rule()
$tb->rule;
$tb->rule( $char);
$tb->rule( $char, $char1);
$tb->rule( sub { my ($index, $len) = @_; },
sub { my ($index, $len) = @_; },
);
Returns a rule for the table.
A rule is a line of table width that can be used between table lines to provide visual horizontal
divisions, much like column separators provide vertical visual divisions. In its basic form
(returned by the first call) it looks like a table line with no data, hence a blank line except for
the non-blank parts of any column-separators. If one character is specified (the second call), it
replaces the blanks in the first form, but non-blank column separators are retained. If a second
character is specified, it replaces the non-blank parts of the separators. So specifying the same
character twice gives a solid line of table width. Another useful combo is "$tb-<rule( '-', '+')",
together with separators that contain a single nonblank "|", for a popular representation of line
crossings.
"rule()" uses the column separators for the title section if there is a difference.
If callbacks are specified instead of the characters, then they receive the index of the section of
the rule they need to render and its desired length in characters, and should return the string to
put there. The indexes given are 0 based (where 0 is either the left column separator or the leftmost
cell) and the strings will be trimmed or extended in the replacement.
body_rule()
"body_rule()" works like <rule()>, except the rule is generated using the column separators for the
table body.
Warning Control
warnings()
Text::Table->warnings();
Text::Table->warnings( 'on');
Text::Table->warnings( 'off'):
Text::Table->warnings( 'fatal'):
The "warnings()" method is used to control the appearance of warning messages while tables are
manipulated. When Text::Table starts, warnings are disabled. The default action of "warnings()" is
to turn warnings on. The other possible arguments are self-explanatory. "warnings()" can also be
called as an object method ("$tb->warnings( ...)").
VERSION
This document pertains to Text::Table version 1.121
BUGS
o auto alignment doesn't support alternative characters for the decimal point. This is actually a bug
in the underlying Text::Aligner by the same author.
AUTHOR
MAINTAINER
Shlomi Fish, <http://www.shlomifish.org/> - CPAN ID: "SHLOMIF".
ORIGINAL AUTHOR
Anno Siegel
CPAN ID: ANNO
siegel@zrz.tu-berlin.de
http://www.tu-berlin.de/~siegel
COPYRIGHT
Copyright (c) 2002 Anno Siegel. All rights reserved. This program is free software; you can redistribute
it and/or modify it under the terms of the ISC license.
(This program had been licensed under the same terms as Perl itself up to version 1.118 released on 2011,
and was relicensed by permission of its originator).
The full text of the license can be found in the LICENSE file included with this module.
SEE ALSO
Text::Aligner, perl(1) .
perl v5.12.3 2011-06-10 Text::Table(3pm)