RE exact match

[nk28]

I am having problem in re module of python.

when i do a call of match function it returns true if first of the expression is true.

For Eg :- Expression like ([a-z]+([+][a-z])*) to denote
(a-z)^* + (a-z)^* returns true for ab+ and ab+12

What is the correct method to match exact expression in re module of python ??

That is above 123 should not be accepted but it still is.........

Thanxx a lot !!

[bvdet]

If I understand your question correctly, the following expression will match 'ab+' and 'ab+df' but will not match 'ab+12':

patt = r'([a-z]+)[+]([a-z]*)$'

[Glenton]

These docs should help. I don't entirely understand your question, as it's not clear (to me at least) what is regular expressions and what is strings you're trying to match to!

But * means "0 or more of the preceding character(s)"
and + means "1 or more of the preceding character(s)"

[nk28]

What i want to know is if there 's a function in python that does exact matching of regular expression.

The docs say that the match function returns true if some part of it gets accepted.....

Thanxx a lot....

[Glenton]

The more detailed docs give you the answer, I think.

But @bvdet has got the answer as usual. The $ character matches the end of the string. So with the pattern as:

pat=r'([a-z]+)[+]([a-z]*)$'
 

This returns a match:

In [3]: re.match(pat,"ab+cd")
Out[3]: <_sre.SRE_Match object at 0x992d3c8>
 

But these do not:

In [4]: re.match(pat,"ab+12")
 
In [5]: re.match(pat,"ab1"+"ab")
 
In [6]: re.match(pat,"ab+cd1234")