[Python-Dev] Any reason that any()/all() do not take a predicateargument?

[Bill Janssen]

> >> seq = [1,2,3,4,5]
> >> if any(seq, lambda x: x==5):
> >> ...
> >>
> >> which is clearly more readable than
> >>
> >> reduce(seq, lambda x,y: x or y==5, False)
> > 
> > How about this?
> > 
> > 	if any(x==5 for x in seq):
> 
> Aren't all of these equivalent to:
> 
> if 5 in seq:
>      ...

Yeah, but you can't do more complicated expressions that way, like

      any(lambda x: x[3] == "thiskey")

I think it makes a lot of sense for any and all to take optional
predicate function arguments.

But perhaps the syntax should be:

      X in SEQ

If X is a predicate function, it gets called to determine "equals"; if
an expression or other object, the normal rules apply.  Of course,
then you couldn't look for a function in a set of functions...

I suppose

      (len([x for x in SEQ if PRED(x)]) > 0)

will suffice for now.  Obvious enough, Martin?

Bill