noniterators.py 文件源码

def oldfilter(*args):
        """
        filter(function or None, sequence) -> list, tuple, or string

        Return those items of sequence for which function(item) is true.
        If function is None, return the items that are true.  If sequence
        is a tuple or string, return the same type, else return a list.
        """
        mytype = type(args[1])
        if isinstance(args[1], basestring):
            return mytype().join(builtins.filter(*args))
        elif isinstance(args[1], (tuple, list)):
            return mytype(builtins.filter(*args))
        else:
            # Fall back to list. Is this the right thing to do?
            return list(builtins.filter(*args))

    # This is surprisingly difficult to get right. For example, the
    # solutions here fail with the test cases in the docstring below:
    # http://stackoverflow.com/questions/8072755/