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List slices

4 September, 2015 - 14:38

The slice operator also works on lists:

>>> t = ['a', 'b', 'c', 'd', 'e', 'f']>>> t[1:3]['b', 'c']>>> t[:4]['a', 'b', 'c', 'd']>>> t[3:]['d', 'e', 'f']

If you omit the first index, the slice starts at the beginning. If you omit the second, the slice goes to the end. So if you omit both, the slice is a copy of the whole list.

>>> t[:]['a', 'b', 'c', 'd', 'e', 'f']

Since lists are mutable, it is often useful to make a copy before performing operations that fold, spindle or mutilate lists.

A slice operator on the left side of an assignment can update multiple elements:

>>> t = ['a', 'b', 'c', 'd', 'e', 'f']>>> t[1:3] = ['x', 'y']>>> print t['a', 'x', 'y', 'd', 'e', 'f']