Python regular expressions return true/false
PythonRegexPython Problem Overview
Using Python regular expressions how can you get a True
/False
returned? All Python returns is:
<_sre.SRE_Match object at ...>
Python Solutions
Solution 1 - Python
If you really need True
or False
, just use bool
>>> bool(re.search("hi", "abcdefghijkl"))
True
>>> bool(re.search("hi", "abcdefgijkl"))
False
As other answers have pointed out, if you are just using it as a condition for an if
or while
, you can use it directly without wrapping in bool()
Solution 2 - Python
Match
objects are always true, and None
is returned if there is no match. Just test for trueness.
if re.match(...):
Solution 3 - Python
Ignacio Vazquez-Abrams is correct. But to elaborate, re.match()
will return either None
, which evaluates to False
, or a match object, which will always be True
as he said. Only if you want information about the part(s) that matched your regular expression do you need to check out the contents of the match object.
Solution 4 - Python
Here is my method:
import re
# Compile
p = re.compile(r'hi')
# Match and print
print bool(p.match("abcdefghijkl"))
Solution 5 - Python
One way to do this is just to test against the return value. Because you're getting <_sre.SRE_Match object at ...>
it means that this will evaluate to true. When the regular expression isn't matched you'll the return value None, which evaluates to false.
import re
if re.search("c", "abcdef"):
print "hi"
Produces hi
as output.
Solution 6 - Python
You can use re.match()
or re.search()
.
Python offers two different primitive operations based on regular expressions: re.match()
checks for a match only at the beginning of the string, while re.search()
checks for a match anywhere in the string (this is what Perl does by default). refer this