"Andrew Nelsen" <[EMAIL PROTECTED]> wrote
>I was wondering, recently, the most expedient way to take a string
>with
> [EMAIL PROTECTED]&*] and alpha-numeric characters [ie. "[EMAIL
> PROTECTED]@*$g@)$&^@&^$F"]
> and
> place all of the letters in a string or list. I thought there could
> be
> obvious ways:
The most obvious way is to use the filter() function
newstr = filter(lambda c: c.isalpha(), oldstr)
filter filters outs values from a sequence that match the given
operation.
or using list comprehensions:
newstr = ''.join([c for c in oldstr if c.isalpha()])
BTW, I know this wasn't real code but...
> import string
you shouldn't use the string module now, string objects make
it nearly redundant
> list = {}
this defines a dictionary not a list.
and the world list is a bui8lt in function, if you use it as a
name you will not be able to convert things to lists!
> string = "@*&^$&[EMAIL PROTECTED](&@$*(&[EMAIL PROTECTED](*&*(&c^&%&^%"
string is the name of the module you imported, if you use
a name thats already in use you will hide that name, in
this case you wouldn't be able to use the string module!
> for x in string:
> if x <is in string.letters?>
> list = list + [x]
This would almost work, except the append() method would probably
be better than list addition. In fact its almost exactly what my list
comprehension does above.
> B) Delete all the characters in the string that don't match
> string.letters:
>
> No idea...strip()?
del() for a list, but you can't modify strings in place so youd
need to convert to a list and then back again. The first method is
better.
HTH,
--
Alan Gauld
Author of the Learn to Program web site
http://www.freenetpages.co.uk/hp/alan.gauld
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