Simple regular expression, why this not works?

re.comp开发者_如何学JAVAile("a[b|c]d").findall("akjh adc abc abbd acd") 

why this returns only

['acd']

not

['abd', 'acd']

?

EDIT:

I gave wrong example... thats why. Post can be deleted..

The regular expression will match a string starting with a, followed by b or c and then d. That is:

'abd'

or

'acd'

Your regex matches any string starting with a, ending with d and with either a b, a | or a c.

If you are looking for have either a b or a c between a and d, you use the square brackets without the pipe (a[bc]d) or you use parenthesis with the pipe (a(b|c)d). The square brackets means that any character between them is accepted one time (including the |); the parenthesis means that any of the regexes separated by | are accepted - and in this case you would have two regexes, one matching b only and one matching c only.

I find the first option the best one. However, these regexes would not match abc in any way. There are a lot of regexes which can match both strings, such as a[bc][cd] or (which makes more sense to me) a(bc|cd).

HTH.

you don't need the pipe in the character class

re.compile("a[bc]d").findall("akjh adc abc abbd acd") 

the pattern says, search for a, then b or c (ie, anything in the character class) and then d. So the regex only returns 1 finding.