How to make all lists in a list of lists the same length by adding to them

Question

I have a nested list which contains lists filled with strings. What I am trying to do is make each list in this nest the same length as the longest available list in that n

Answer 1

The expression 'null' * (len(maxSS7) - len(row)) creates one potentially very long string.

Use

row.extend('null' for _ in xrange(maxSS7 - len(row)))

instead. The generator expression lets you avoid creating an extra list object just to extend row.

>>> ['null' * 2]
['nullnull']
>>> ['null' for _ in xrange(2)]
['null', 'null']

But the .extend call itself is never reached, as you if statement is testing the wrong thing; change it to:

 if len(row) < maxSS7:

maxSS7 is aready a number (the length of the longest list); asking that number for it's length is not what you were looking for.