Array of Chars to String

[James Stroud]

Hello,

I am looking for a nice way to take only those charachters from a string that 
are in another string and make a new string:

>>> astr = "Bob Carol Ted Alice"
>>> letters = "adB"
>>> some_func(astr,letters)
"Bad"

I can write this like this:

astr = "Bob Carol Ted Alice"
letters = "adB"

import sets
alist = [lttr for lttr in astr if lttr in Set(letters)]
newstr = ""
for lttr in alist:
  newstr += lttr

But this seems ugly. I especially don't like "newstr += lttr" because it makes 
a new string every time. I am thinking that something like this has to be a 
function somewhere already or that I can make it more efficient using a 
built-in tool.

Any ideas?

James

-- 
James Stroud
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095

http://www.jamesstroud.com/