"Jorge Godoy" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > Wildemar Wildenburger <[EMAIL PROTECTED]> writes: > >> I don't know how else to call what I'm currently implementing: An object >> that >> behaves like a list but doesn't store it's own items but rather pulls >> them >> from a larger list (if they match a certain criterion). >> Changes to the filter are instantly reflected in the underlying list. >> Clear enough? > > It looks like you're implementing a callable to me. This is a method that > returns results based on some input -- here your original list and filter. > > Then you'll use this method wherever you need that filtered list. > >> Ok, so I figured that this is generic enough to be found in some standard >> module already (I've had this often enough: Painfully implementing s/th >> and >> then finding it in the libs some weeks later.). > > I don't believe it is generic. Nobody knows your data specs or filtering > needs. > >> Any pointers? > > Use of list comprehension might make it easier to code this: > > > def myCallable(my_list, filter): > filtered_list = [(item) for item in my_list if filter(item)] > return filtered_list > > > Example of full code: > >>>> test_list = range(10) >>>> filter = lambda x: not x%2 >>>> def myCallable(list, filter): > ... filtered_list = [(item) for item in list if filter(item)] > ... return filtered_list > ... >>>> myCallable(test_list, filter) > [0, 2, 4, 6, 8] >>>> for item in myCallable(test_list, filter): > ... print "See? I'm", item > ... > See? I'm 0 > See? I'm 2 > See? I'm 4 > See? I'm 6 > See? I'm 8 >>>> > > > -- > Jorge Godoy <[EMAIL PROTECTED]>
Functionally-speaking, there is the filter built-in that does this same thing: >>> data = range(10) >>> odds = filter(lambda x : x % 2, data) >>> evens = filter(lambda x : x % 2 != 1, data) >>> odds [1, 3, 5, 7, 9] >>> evens [0, 2, 4, 6, 8] -- Paul -- http://mail.python.org/mailman/listinfo/python-list
