Help with regular expression

[Stephen Boulet]

I'm trying to write an RE to match a string that might or might not be
ther and everything past it up to another string that might or might not
be there and everything past it to a third string that might or might
not be there and everything past it.

Say my strings are "STRING1", "STRING2", and "String3".

Would the re be:

r'((STRING1.*)( STRING2.*)(STRI NG3.*))'

The goal is to separate the groups by newlines, but I only want the
first group to match up to the second group and the second to match up
to the third.

Normally I would achieve this by typing:

pat = re.compile(r'(( STRING1.*)(STRI NG2.*)(STRING3. *))')
m = pat.findall(s)
s = '\n\n'.join(m[0])

but the first group would seem to match everything.

How can I get it to do what I want?

-- Stephen

[anton muhin]

Re: Help with regular expression

Stephen Boulet wrote:
[color=blue]
> I'm trying to write an RE to match a string that might or might not be
> ther and everything past it up to another string that might or might not
> be there and everything past it to a third string that might or might
> not be there and everything past it.
>
> Say my strings are "STRING1", "STRING2", and "String3".
>
> Would the re be:
>
> r'((STRING1.*)( STRING2.*)(STRI NG3.*))'
>
> The goal is to separate the groups by newlines, but I only want the
> first group to match up to the second group and the second to match up
> to the third.
>
> Normally I would achieve this by typing:
>
> pat = re.compile(r'(( STRING1.*)(STRI NG2.*)(STRING3. *))')
> m = pat.findall(s)
> s = '\n\n'.join(m[0])
>
> but the first group would seem to match everything.
>
> How can I get it to do what I want?
>
> -- Stephen
>[/color]

Try non-greedy wildcards: r'((STRING1.*?) (STRING2.*?)(ST RING3.*?))'
- - -

should do the trick.

hth,
anton.

[Ulrich Petri]

Re: Help with regular expression

"anton muhin" <antonmuhin.REM OVE.ME.FOR.REAL .MAIL@rambler.r u> schrieb im
Newsbeitrag news:bkbssb$102 f$1@news.peterl ink.ru...[color=blue]
> Stephen Boulet wrote:
>[color=green]
> > I'm trying to write an RE to match a string that might or might not be
> > ther and everything past it up to another string that might or might not
> > be there and everything past it to a third string that might or might
> > not be there and everything past it.
> >[/color]
>
> Try non-greedy wildcards: r'((STRING1.*?) (STRING2.*?)(ST RING3.*?))'
> - - -
>[/color]

Since you said that each of the three strings might or not be there you
would need:

r'((STRING1.*?) ?(STRING2.*?)?( STRING3.*?)?)'

Ciao Ulrich