Create nice column output in python

Question

Since Python 2.6+, you can use a format string in the following way to set the columns to a minimum of 20 characters and align text to right.

table_data = [
    ['a', 'b', 'c'],
    ['aaaaaaaaaa', 'b', 'c'], 
    ['a', 'bbbbbbbbbb', 'c']
]
for row in table_data:
    print("{: >20} {: >20} {: >20}".format(*row))

Output:

               a                    b                    c
      aaaaaaaaaa                    b                    c
               a           bbbbbbbbbb                    c

data = [['a', 'b', 'c'], ['aaaaaaaaaa', 'b', 'c'], ['a', 'bbbbbbbbbb', 'c']]

col_width = max(len(word) for row in data for word in row) + 2  # padding
for row in data:
    print "".join(word.ljust(col_width) for word in row)

a            b            c            
aaaaaaaaaa   b            c            
a            bbbbbbbbbb   c   

What this does is calculate the longest data entry to determine the column width, then use .ljust() to add the necessary padding when printing out each column.

I came here with the same requirements but @lvc and @Preet's answers seems more inline with what column -t produces in that columns have different widths:

>>> rows =  [   ['a',           'b',            'c',    'd']
...         ,   ['aaaaaaaaaa',  'b',            'c',    'd']
...         ,   ['a',           'bbbbbbbbbb',   'c',    'd']
...         ]
...

---

>>> widths = [max(map(len, col)) for col in zip(*rows)]
>>> for row in rows:
...     print "  ".join((val.ljust(width) for val, width in zip(row, widths)))
...
a           b           c  d
aaaaaaaaaa  b           c  d
a           bbbbbbbbbb  c  d

This is a little late to the party, and a shameless plug for a package I wrote, but you can also check out the Columnar package.

It takes a list of lists of input and a list of headers and outputs a table-formatted string. This snippet creates a docker-esque table:

from columnar import columnar

headers = ['name', 'id', 'host', 'notes']

data = [
    ['busybox', 'c3c37d5d-38d2-409f-8d02-600fd9d51239', 'linuxnode-1-292735', 'Test server.'],
    ['alpine-python', '6bb77855-0fda-45a9-b553-e19e1a795f1e', 'linuxnode-2-249253', 'The one that runs python.'],
    ['redis', 'afb648ba-ac97-4fb2-8953-9a5b5f39663e', 'linuxnode-3-3416918', 'For queues and stuff.'],
    ['app-server', 'b866cd0f-bf80-40c7-84e3-c40891ec68f9', 'linuxnode-4-295918', 'A popular destination.'],
    ['nginx', '76fea0f0-aa53-4911-b7e4-fae28c2e469b', 'linuxnode-5-292735', 'Traffic Cop'],
]

table = columnar(data, headers, no_borders=True)
print(table)

Or you can get a little fancier with colors and borders.

To read more about the column-sizing algorithm and see the rest of the API you can check out the link above or see the Columnar GitHub Repo

You have to do this with 2 passes:

1. get the maximum width of each column.
2. formatting the columns using our knowledge of max width from the first pass using str.ljust() and str.rjust()