[Tutor] Extending a list within a list comprehension

[John Fouhy]

On 12/04/06, Victor Bouffier <victor at grupocdm.com> wrote:
> elements = [
> (codigo, [ cant, importe, porc]),
> (codigo, [ cant, importe, porc]),
> ...
> ]
>
> And I want to sort descending on 'importe', which is x[1][1] for x in
> elements.

In python 2.4, you could achieve this by saying:

elements.sort(key=lambda x: x[1][1])

In earlier versions of python, you can do:

elements.sort(lambda x, y: cmp(x[1][1], y[1][1]))

(but this is less efficient than key= in 2.4)

There's also the decorate-sort-undecorate idiom:

dec = [(x[1][1], x) for x in elements]
dec.sort()
elements = [x[1] for x in dec]

--
John.