Learn Web Development with Python

Indexing and slicing strings

When manipulating sequences, it's very common to have to access them at one precise position (indexing), or to get a subsequence out of them (slicing). When dealing with immutable sequences, both operations are read-only.

While indexing comes in one form, a zero-based access to any position within the sequence, slicing comes in different forms. When you get a slice of a sequence, you can specify the start and stop positions, and the step. They are separated with a colon (:) like this: my_sequence[start:stop:step]. All the arguments are optional, start is inclusive, and stop is exclusive. It's much easier to show an example, rather than explain them further in words:

>>> s = "The trouble is you think you have time." ...