Re.match always returning None in python

Question

I'm trying to make a very simple regex match ( the negation of all printable anscii characters other then '[' and ']'). When I tested my pattern in regex pal I got the matching that I wanted. Then I moved to my python unit test and my match never returns true

def testChatChars(string):
   return re.match('[^\x20-\x5A\x5C\x5E-\x7E]', string) is not None

print("testing Chat validation") 
print(testChatChars("") == False)
print(testChatChars("this is a valid chat message") == True)
print(testChatChars("9999abcdefghijklmnopqrxtuvxyz ABCDEFGHIJKLMNOP!@#$(^&*(&%$^^)*)!{},.;'\|?/7") == True )
print(testChatChars("this is not [ valid chat message") == False)
print(testChatChars("this is not ] valid chat message") == False)
print(testChatChars("9999abcdefghijklmnopqrxtuvxyz [][][[][]ABCDEFGHIJKLMNOP!@#$(^&*(&%$^^)*)!{}[],.;'\|?/7ونِكود碼標準萬國") == False)

Which is returning

False //should be true
False //should be true
False //should be true
True
True
True

re.match is always returning none for some reason.

UPDATE: tried to change my code in the suggested fashion new output is

False
False
True
False
False
False

falsetru · Accepted Answer · 2013-06-12 07:08:32Z

2

def testChatChars(string):
   return re.match(r'[\x20-\x5A\x5C\x5E-\x7E]+$', string) is not None

answered Jun 12, 2013 at 7:08

falsetru

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3 Comments

AlexLordThorsen Over a year ago

This worked for me. Why do I not need a ^ character and what does the +$ symbol do?

falsetru Over a year ago

@Rawrgulmuffins, I recommend you read docs.python.org/2/howto/regex.html .

AlexLordThorsen Over a year ago

fair enough, I just made the (apparently wrong) assumption that python regex was perl regex.

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