Create range from tuple (slice.indices())

Question

At the bottom of this page from the Python 2.3 docs it says:

slice objects now have a method indices(length) which, given the length of a sequence, returns a (start, stop, step) tuple that can be passed directly to range()

Here is some test code:

s = slice(0, 10)
r = range(s.indices(10))

It throws a TypeError:

TypeError: range() integer end argument expected, got tuple.

Why doesn't this work?

In my use case, range() is called in a library and I need to supply a slice that is used this way.

Answer 1

Try this:

r = range(*s.indices(10))

Explanation: range() expects up to three integers as arguments, so we need to unpack the tuple of integers returned by indices() using *, the splat operator.