Columnize - Format an Array as a Column-aligned String

In showing a long lists, sometimes one would prefer to see the value arranged aligned in columns. Some examples include listing methods of an object, listing debugger commands, or showing a numeric array with data aligned.

Setup

    $ irb
    >> require 'columnize'
    => true

With numeric data

>> a = (1..10).to_a
=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

>> a.columnize
=> "1  2  3  4  5  6  7  8  9  10"

>> puts a.columnize :arrange_array => true, :displaywidth => 10
[ 1, 2, 3,
  4, 5, 6,
  7, 8, 9,
 10]
=> nil

>> puts a.columnize :arrange_array => true, :displaywidth => 20
[1, 2, 3,  4, 5, 6,
 7, 8, 9, 10]
=> nil

With String data

>> g = %w(bibrons golden madascar leopard mourning suras tokay)
=> ["bibrons", "golden", "madascar", "leopard", "mourning", "suras", "tokay"]

>> puts g.columnize :displaywidth => 15
bibrons   suras
golden    tokay
madascar
leopard
mourning
=> nil

>> puts g.columnize :displaywidth => 19, :colsep => ' | '
bibrons  | mourning
golden   | suras
madascar | tokay
leopard
=> nil

>> puts g.columnize :displaywidth => 18, :colsep => ' | ', :ljust => false
bibrons | suras
 golden | tokay
madascar
 leopard
mourning
=> nil

Using Columnize.columnize

>> Columnize.columnize(a)
=> "1  2  3  4  5  6  7  8  9  10"

>> puts Columnize.columnize(a, :displaywidth => 10)
1  5   9
2  6  10
3  7
4  8
=> nil

>> Columnize.columnize(g)
=> "bibrons  golden  madascar  leopard  mourning  suras  tokay"

>> puts Columnize.columnize(g, :displaywidth => 19, :colsep => ' | ')
bibrons  | mourning
golden   | suras
madascar | tokay
leopard
=> nil

Credits

This is adapted from a method of the same name from Python's cmd module.

Security contact information

To report a security vulnerability, please use the Tidelift security contact. Tidelift will coordinate the fix and disclosure.

Warranty

You can redistribute it and/or modify it under either the terms of the GPL version 2 or the conditions listed in COPYING

Other stuff

Authors: Rocky Bernstein [email protected] and Martin Davis

License: Copyright (c) 2011,2013, 2020 Rocky Bernstein