You have three ways to do what you want :
First wayt is to use lambda. Then, you want to write :
[color=blue][color=green][color=darkred]
>>> map(lambda x: re.sub("[a-z]", "", x), test)[/color][/color][/color]
Second is to use regular named function :
[color=blue][color=green][color=darkred]
>>> def remove_letters( s ):[/color][/color][/color]
.... re.sub("[a-z]", "", s)[color=blue][color=green][color=darkred]
>>> map(remove_letters, test)[/color][/color][/color]
A third way would be to use the "pseudo-currying" described there :
http://www.python.org/moin/PythonDecoratorLibrary
In fact, you need a small generalisation :
[color=blue][color=green][color=darkred]
>>> class curried(object):[/color][/color][/color]
.... def __init__(self, func, *a, **kw):
.... self.func = func
.... self.args = a
.... self.kwords = kw
.... def __call__(self, *a, **kw):
.... args = self.args + a
.... kwords = dict(self.kwords)
.... kwords.update(kw)
.... if len(args)+len(kwords) < self.func.func_code.co_argcount:
.... return curried(self.func, *args, **kwords)
.... else:
.... return self.func(*args, **kwords)
The difference is you can handle the kwords with that version !
Then you want to write this :
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>>> curried_sub = curried(re.sub)
>>> map(curried_sub("[a-z]", "", count=0), test)[/color][/color][/color]
My opinion is : the simplest and best solution more "pythonic" is the
second one ! The third one is interesting but work only for functions
written in Python ! (Hopefully the re.sub function is written in
Python). The biggest problem with the first one is that lambda are
planned to disappear in future Python versions ...
Pierre
Stu a écrit :[color=blue]
> I have recently switched over to Python from Perl. I want to do
> something like this in Python:
>
> @test = ("a1", "a2", "a3");
> map {s/[a-z]//g} @test;
> print @test;
>
> However, I take it there is no equivalent to $_ in Python. But in that
> case how does map pass the elements of a sequence to a function? I
> tried the following, but it doesn't work because the interpreter
> complains about a missing third argument to re.sub.
>
> import re
> test = ["a1", "a2", "a3"]
> map(re.sub("[a-z]", ""), test)
> print test
> Thanks in advance.
>
> Regards,
> Stuart <stuart AT zapata DOT org>
>[/color]
map in Python 
