re Challenge: More Compact?

[Greg Jorgensen]

Translating the Perl version to Python leads to un-Pythonic code. How about
this:

def valid_ip(ip):
    iprange = range(256)
    return type(ip) == type('') and \
        [x.isdigit() and long(x) in iprange
         for x in ip.split('.')] == [1,1,1,1]


Or this, if you don't like list comprehensions:

def valid_ip(ip):
    iprange = range(256)
    return type(ip) == type('') and \
        map(lambda x, iprange=iprange:
            x.isdigit() and long(x) in iprange, ip.split('.')) \
        == [1,1,1,1]


No regular expressions, no other modules, checks the type of input
parameter, safe from type conversion errors, and looks for exactly four
integers in the range [0,255].

Greg Jorgensen
PDXperts LLC
Portland, Oregon, USA