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.

This is a Python module to format a simple (i.e. not nested) list into aligned columns. A string with embedded newline characters is returned.

Setup

$ python
>>> import columnize

With String data

Each column is only as wide as necessary. By default, columns are separated by two spaces; one was not legible enough. Set colsep to adjust the string separate columns. Set displaywidth to set the line width.

>>> g = ('bibrons', 'golden', 'madascar', 'leopard', 'mourning', 'suras', 'tokay')
>>> print(columnize.columnize(g, displaywidth=15))
bibrons   suras
golden    tokay
madascar
leopard
mourning

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

>>> print(columnize.columnize(g, displaywidth=18, colsep=' | ', ljust=False))
bibrons | suras
 golden | tokay
madascar
 leopard

Normally, consecutive items go down from the top to bottom from the left-most column to the right-most. If arrange_vertical is set false, consecutive items will go across, left to right, top to bottom.

With numeric data

>>> print(columnize.columnize(['1', '2', '3', '4'], displaywidth=6)) # => '1  3\n2  4\n'
1  3
2  4

>>> print(columnize.columnize(list(range(1,6)), displaywidth=8))
1  3  5
2  4

By default entries are left justified:

>>>  print(columnize.columnize(list(range(1,16)), displaywidth=10))

1  6   11
2  7   12
3  8   13
4  9   14
5  10  15

but you can change that with ljust or if arrange_array is set to True:

>>>  print(columnize.columnize(list(range(1,16)), displaywidth=10, ljust=False))
1   6  11
2   7  12
3   8  13
4   9  14
5  10  15

>>> print(columnize.columnize(list(range(1,5)), opts={'arrange_array':True, 'displaywidth':6}))
[1, 2
 3, 4]

Credits

This module (essentially one function) was adapted from a private method of the same name from Python's cmd module. Some adjustments and generalizations have been made.

Other stuff

Authors: Rocky Bernstein rockyb@rubyforge.org

License: MIT