check if regeular expression has results

[Bruno Desthuilliers]

Neil Cerutti a écrit :

Newgroups are a poor substitute for the docs. For one thing,
newsgroups sometimes contain cranky people who say, "RTFM!" The
docs will never do that.

And for completness, here are the relevant parts of TheFineManual(tm):
http://docs.python.org/lib/module-re.html
http://www.amk.ca/python/howto/regex/

 

[shahargs]

Hi,
I'm looking for the best way to check if regular expression return
true (it's mean - there is a match). for example, i want "if" that
check if this regular expression: .*born.*to.* has a match.

What's the way to do that simply?

Thanks a lot,
Shahar.

 

[Marc 'BlackJack' Rintsch]

I'm looking for the best way to check if regular expression return
true (it's mean - there is a match). for example, i want "if" that
check if this regular expression: .*born.*to.* has a match.

What's the way to do that simply?

Simply use an ``if`` on the result of the search or match. If the regular
expression doesn't match `None` is returned, which is `False` in a boolean
context, otherwise a match object is returned, which is `True` in a
boolean context.

Ciao,
Marc 'BlackJack' Rintsch

 

[Patrick Doyle]

Hi,
I'm looking for the best way to check if regular expression return
true (it's mean - there is a match). for example, i want "if" that
check if this regular expression: .*born.*to.* has a match.

What's the way to do that simply?

How about

import re
re.match(".*born.*to", "This is a test")
re.match(".*born.*to.*", "This test was born so that it worked too.")

(Try these at the python prompt)

The first call to 're.match()' returns 'None' which will fail an if
test. The second one returns a match object, which evaluates to TRUE
in an if test.

--wpd

 

[Neil Cerutti]

Hi,
I'm looking for the best way to check if regular expression return
true (it's mean - there is a match). for example, i want "if" that
check if this regular expression: .*born.*to.* has a match.

What's the way to do that simply?

Newgroups are a poor substitute for the docs. For one thing,
newsgroups sometimes contain cranky people who say, "RTFM!" The
docs will never do that.

 

[Steve Holden]

Hi,
I'm looking for the best way to check if regular expression return
true (it's mean - there is a match). for example, i want "if" that
check if this regular expression: .*born.*to.* has a match.

What's the way to do that simply?

A failed match returns None. A successful match returns a match object.
So the easiest way to check for a successful match is

pat = re.compile(...)
....
m = pat.match(some_string)
if m:
... you got a match ...
else:
... you didn't ...

regards
Steve
--
Steve Holden +1 571 484 6266 +1 800 494 3119
Holden Web LLC/Ltd http://www.holdenweb.com
Skype: holdenweb http://del.icio.us/steve.holden
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