Adding spaces to items in list (Python)

Question

I'm a Python noob and I need some help for a simple problem.

What I need to do is create a list with 3 items and add spaces before and after every item.

For example: l1 = ['a', 'bb', 'c']
should be transformed into: [' a ',' bb ',' c ']

I was trying to write something like this:

lst = ['a', 'bb', 'c']
for a in lst:
    print '  a  '

...and so on for the other elements, but I get a syntax error. Can anyone suggest me a working way to do this? Thanks.

Answer 1

As always, use a list comprehension:

lst = [' {0} '.format(elem) for elem in lst]

This applies a string formatting operation to each element, adding the spaces. If you use python 2.7 or later, you can even omit the 0 in the replacement field (the curly braces).

Answer 2

[ ' {} '.format(x) for x in lst ]

EDIT for python 3.6+:

you can use f-strings instead, see docs: https://www.python.org/dev/peps/pep-0498/

the example above would look like:

[ f' {x} ' for x in lst ]