Question

I wrote up this regular expression:

p = re.compile(r'''
\[\[            #the first [[
[^:]*?          #no :s are allowed
.*?             #a bunch of chars
(
\|              #either go until a |
|\]\]           #or the last ]]
)
                ''', re.VERBOSE)

I want to use re.findall to get all the matching sections of some string. I wrote some test code, but it gives me bizarre results.

This code

g = p.finditer('   [[Imae|Lol]]     [[sdfef]]')
print g
for elem in g:
    print elem.span()
    print elem.group()

gives me this output:

(3, 10)
[[Imae|
(20, 29)
[[sdfef]] 

Makes perfect sense right? But when I do this:

h = p.findall('   [[Imae|Lol]]     [[sdfef]]')
for elem in h:
    print elem

the output is this:

|
]]  

Why isn’t findall() printing out the same results as finditer??

Answer 1

Findall returns a list of matching groups. The parantheses in your regex defines a group that findall thinks you want, but you don’t want groups. (?:...) is a non-capturing paranthesis. Change your regex to:

'''
\[\[            #the first [[
[^:]*?          #no :s are allowed
.*?             #a bunch of chars
(?:             #non-capturing group
\|              #either go until a |
|\]\]           #or the last ]]
)
                '''