Why does my RegExp match in RegExr, but not in Python?

Question

regexp = re.compile('[A-Z]\\d{4}')
prefix = regexp.match("\"O1533_FOO\" INTEGER NOT NULL ,")

Prefix is None, but I expected it to be "O1533".

When I use the web based tool http://regexr.com/ it works.

http://regexr.com/3bag5

I tried to escape the \ with different numbers of \s, and I also tried delimiting /s. Could not get it to work.

Can some RegExp expert please fix my expression?

Because `re.match` match the string form beginning . you need `re.search`. — Mazdak, Jul 01 '15 at 15:09

score 7 · Accepted Answer · answered Jul 01 '15 at 15:08

Because you should replace match with search.

match tries to match the string from the beginning, and \"O1533_FOO\" INTEGER NOT NULL , doesn't begin with something that matches [A-Z], hence it fails.

See search() vs. match():

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).

Why does my RegExp match in RegExr, but not in Python?

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