python sort without lambda expressions

Question

I often do sorts in Python using lambda expressions, and although it works fine, I find it not very readable, and was hoping there might be a better way. Here is a typical use

Answer 1

You can use the __getitem__ method of the list x. This behaves the same as your lambda and will be much faster since it is implemented as a C function instead of a python function:

>>> x = [12, 101, 4, 56]
>>> y = range(len(x))
>>> sorted(y, key=x.__getitem__)
[2, 0, 3, 1]