Proposal: [... for ... while cond(x)]

[Diez B. Roggisch]

> No, the list comprehension lets you write an expression directly avoiding a 
> function call, and it also allows you to add in a condition which can be 
> used to filer the sequence. Your proposal adds nothing.

It does. Consider this:

whatever = [x for x in xrange(1000000000) while  x < 10]


That would run only in a splitsecond of what the whole listcomp would.


Yet I still fail to see that this is a really useful use-case. takewhile 
is easily abstracted away as map and reduce and filter are using lambda 
- which I'm a modest supporter of.

But functions that are monotonic such that the takewhile really offers a 
advantage over the much more general listcomp + if are IMHO way to 
seldom to justify a new syntax.

The overall complexity is still O(n).

Regards,

Diez