Speeding up a regular expression

[Chris Liechti]

>>     lines = string.split(inputString,"\n")
       retlist = []

>>     for line in lines:
>>         if myRe.match(line):
               retlist.append(line)
       return '\n'.join(retlist) #newer python versions

##       return string.join(retlist,'\n') #for py 1.5.2:


extending strings does require lots memory allocations and compying the 
strings, a list is far more efficient when changes are made on it.

if the data comes from a file you could also use f.readlines() and omit 
split().

you could also use "filter()", that moves the python for-loop to the fast 
loop in C in filter:

return '\n'.join(filter(myRe.match, lines))

hope that helps

chris

-- 
Chris <cliechti at gmx.net>