On Mon, 25 Apr 2005 16:48:46 -0400, Bill Mill <[EMAIL PROTECTED]> wrote:
>On 25 Apr 2005 23:33:48 +0300, Ville Vainio <[EMAIL PROTECTED]> wrote: >> >>>>> "Jeremy" =3D=3D Jeremy Bowers <[EMAIL PROTECTED]> writes: >>=20 >> Jeremy> On Sun, 24 Apr 2005 22:59:12 -0700, Robert Kern wrote: >> >> Never. If you really need a list >> >> >> >> list(x*x for x in xrange(10)) >> >> >> >> Sadly, we can't remove list comprehensions until 3.0. >>=20 >> Jeremy> Why "remove" them? Instead, we have these things called >> Jeremy> "comprehensions" (which, now that I say that, seems a >> Jeremy> rather odd name), and you can control whether they result >> Jeremy> in a list or a generator with () or []. >>=20 >> Still, list comprehensions should be implemented in terms of genexps >> to get rid of the LC variable that is visible outside the scope of the >> LC. >>=20 > >+1 . I think that we should still have the form [genexp] , but without >the dangling variable, and implemented with generator expressions. It >seems to me that it is inconsistent if I can do list(genexp) but not >[genexp] , since they are so similar. Once that happens, we can tell >people who ask the OP's question that [genexp] is just another way to >spell list(genexp), and he should use it if he wants the entire list >constructed in memory. ISTM you have to account for >>> def foo(g): return g ... >>> foo(123) 123 >>> foo(c for c in 'abc') <generator object at 0x02EF154C> >>> [(c for c in 'abc')] [<generator object at 0x02EF158C>] >>> [c for c in 'abc'] ['a', 'b', 'c'] > >> Jeremy> should be relatively simple), it's not worth breaking that >> Jeremy> code. >>=20 >> Well, the code that relies on the dangling variable deserves to break. > >Agreed. > Probably ;-) Regards, Bengt Richter -- http://mail.python.org/mailman/listinfo/python-list
