Slice Notation

In Python, slice notation is used to access a range of elements in an iterable (string, list, tuple, etc.). The general form is:

[start:stop:step]

• start: Starting index, inclusive. Default to start of string at 0 if omitted.
• stop: Stopping index, exclusive. Defaults to end of string at -1 if omitted.
• step: Step/stride. Defaults to 1 if omitted. Can be negative.

A common idiom for reversing a string would be string[::-1]. This traverses the whole string but backward because of the negative step.