Re: Palindrome
 

To remove the characters that are not alphanumeric I would have used
filter :

t=filter(lambda x: x.isalnum(),list(s.lower()))

Pierre

--- In python-list@yahoogroups.com, runic911@a... (Runic911) wrote:
> Does anyone know how i can fix my Palindrome program?
>
> s = raw_input('Enter a String: ')
> punctuation = '%$!*.,-:? ;()\'\"\\'
> i = 0
> h = 0
> t = 0
> p = ''
> z = 0
> while s!= ' ':
> while i <= len(s) - 1:
> punct = s[i]
> if punctuation.find(punct) == -1:
> p = p + punct
> i = i + 1
> t = p.lower()
> t[h] == t[len(t)-1-h]
> --
> http://mail.python.org/mailman/listinfo/python-list

Re: Palindrome
 

Pierre Quentel wrote:

> To remove the characters that are not alphanumeric I would have used
> filter :
>
> t=filter(lambda x: x.isalnum(),list(s.lower()))

or perhaps more clearly...:

t = [ c for c in s.lower() if c.isalnum() ]

Then, "list t comes from a palindromic string s" can be coded as:

return t == t[::-1]

(in Python 2.3).


Alex

Re: Palindrome
 

"Pierre Quentel" <quentel.pierre@wanadoo.fr> wrote in message
news:mailman.715.1068739302.702.python-list@python.org...
> To remove the characters that are not alphanumeric I would have used
> filter :
>
> t=filter(lambda x: x.isalnum(),list(s.lower()))

Why not the more readable list comprehension?

t = [c for c in s.lower() if c.isalnum()]

It's even a tiny bit faster:

....>python lib/timeit.py -s"s='Go Hang a Salami! I\'m a Lasagna Hog!'"
"t=filter(lambda x: x.isalnum(),list(s.lower()))"
10000 loops, best of 3: 91.6 usec per loop

....>python lib/timeit.py -s"s='Go Hang a Salami! I\'m a Lasagna Hog!'" "t =
[c for c in s.lower() if c.isalnum()]"
10000 loops, best of 3: 80.3 usec per loop

--
Francis Avila