In [Python], the [built-in] [function] range(x) returns the [list] [0, 1, 2, ..., x-1]. The standard [idiom] for looping over some index (0 to x-1) is thus [for] i in range(x).

Actually, range is more versatile than that. range(start, end, skip) (with any numeric [argument]s, not just integers) returns a list of values beginning with start, [increment]ed by skip each time, and ending on the last value before end. skip defaults to 1. If there is just one argument, it is taken to be end, and start=0.

It is often much better to use [xrange], a built-in [iterator] [type], an instance of which which returns the same values as an iteration over a range-generated list, but never generates in memory the entire (possibly very long) list of values. The arguments to the [constructor] are identical.

Range (thing)