I have a function to pick out lumps from a list of strings and return them as another list:
def filterPick(lines,regex): result =  for l in lines: match = re.search(regex,l) if match: result += [match.group(1)] return result
Is there a way to reformulate this as a list comprehension? Obviously it's fairly clear as is; just curious.
Thanks to those who contributed, special mention for @Alex. Here's a condensed version of what I ended up with; the regex match method is passed to filterPick as a "pre-hoisted" parameter:
import re def filterPick(list,filter): return [ ( l, m.group(1) ) for l in list for m in (filter(l),) if m] theList = ["foo", "bar", "baz", "qurx", "bother"] searchRegex = re.compile('(a|r$)').search x = filterPick(theList,searchRegex) >> [('bar', 'a'), ('baz', 'a'), ('bother', 'r')]
[m.group(1) for l in lines for m in [regex.search(l)] if m]
The "trick" is the
for m in [regex.search(l)] part -- that's how you "assign" a value that you need to use more than once, within a list comprehension -- add just such a clause, where the object "iterates" over a single-item list containing the one value you want to "assign" to it. Some consider this stylistically dubious, but I find it practical sometimes.
return [m.group(1) for m in (re.search(regex, l) for l in lines) if m]