Python Colon operator

Question

I am trying to port some Python code and I am a little lost on small issue which I would appreciate some advice.

I understand the in operator but I am a little unclear on what the : operator does in this example.

if foo in bar[i][:2]:
    # do something

In http://docs.python.org/tutorial/introduction.html#strings it states that the : operator makes the first two characters only if this is a string. However when used with a list like this is that what will happen as well? So does this just mean the first 2 characters of the string in th

For a more in-depth understanding of how slices can be used via __getitem__, including Ellipsis, see http://stackoverflow.com/questions/509211/pythons-slice-notation — nealmcb, Dec 20 '13 at 01:28

score 7 · Accepted Answer · answered Apr 19 '12 at 07:55

7

This is called list slicing, you already link to the proper part of the documentation in your question. If you find documentation confusing, there is a video tutorial for that:

http://www.youtube.com/watch?v=iD6a0G8MnjA

answered Apr 19 '12 at 07:55

vartec

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score 1 · Answer 2 · answered Apr 19 '12 at 07:10

The behaviour of the operator doesn't depend on where its operands come from - it doesn't matter whether it was a literal, a variable, or a complex expression. The operator does its thing because its operand is a string, not because it was computed in a particular way.

Python Colon operator

2 Answers2

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