Apologies if this comes through twice, I'm having problems with my news
client and/or provider.
On Wed, 05 Jan 2011 16:56:40 -0600, GrayShark wrote:
> In python it's best to build up you functional needs. So two steps.
> First a nand (negative 'and' operation). Then wrap that with a function
> to create two strings of your list element, you''re calling 'word'. By
> the way, list is reserved word, like string. Don't get in the bad habit
> of using it.
Speaking of bad habits:
> def nand( a, b ):
> """nand has to vars. Both must be strings """
> return( ( not eval( a ) ) and ( not eval( b ) ) )
What is the purpose of the two calls to eval, other than potentially
introducing serious security bugs, being slow, and raising exceptions?
def nand(a, b):
return not (a and b)
is faster and safer, and less likely to cause annoyance if somebody
manages to fool you into executing something similar to:
nand("0", "__import__('os').system('# r m -rf /')")
More safely, and works on both Linux and Windows:
nand("0", "__import__('os').system('dir .')")
> Eval of 'Abcd'.isupper() returns False. Ditto 'Abcd'.islower(); negate
> both results, 'and' values, return.
>
> Now wrap 'nand' in packaging an you're cooking with grease.
Eww. Greasy food.
I think the idiom you are thinking of is "now you're cooking with gas",
gas cooking being cleaner, faster and easier than cooking with wood.
> def mixed_case( str ):
> return nand( "'%s'.islower()" % str , "'%s'.isupper()" % str )
I'm afraid that's incorrect, because it returns True for strings that
aren't mixed case:
>>> mixed_case("123")
True
as well as strings that can't be mixed anything on account of being a
single character:
>>> mixed_case("!")
True
A better solution would be:
def ismixed(s):
seen_upper = seen_lower = False
for c in s:
if c.isupper(): seen_upper = True
if c.islower(): seen_lower = True
if seen_upper and seen_lower:
return True
return False
which should return True if and only if the string contains both
lowercase and uppercase characters.
--
Steven
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