How to match a regex with a word and a double quote?-CodePudding

I am writing regex matching in python where the string that needs to be matched is this:

entity("entity1")

I want to match if a string is written in this format and extract the string inside the double quotes, for example:entity1 here.

Note that the it can be anything inside those double quotes and it should still match. For example:

entity("wow")
entity(" 1 2 3 - 5")
entity("!323d de462")

should all match.

I have tried using \entity(\"(.*?)\")\) as regex matching pattern but that doesn't work. Any ideas?

CodePudding user response：

Your attempt was very close.

The correct regex is entity\("(.*?)"\).

You don't need the leading \ since you don't want to escape the e, and you had an extra, erroneous ) in the end.

Extract is possible using .group, as usual:

import re

foo = 'entity("entity1")'
match = re.search(r'entity\("(.*?)"\)', foo)
if match:
    print(match.group(1))

outputs

entity1

CodePudding user response：

Just to add some insight, you can use DEBUG to check your regex, look:

import re

# \" is the same as " and is fixed by black
# \e won't compile at all and will throw an exception when you try to use it in e.g. re.search

p = 'entity("(.*?)"\)\)'
re.compile(p, re.DEBUG)
# re.error: missing ), unterminated subpattern at position 6

# Adding "\" before first bracket
p = 'entity\("(.*?)"\)\)'
re.compile(p, re.DEBUG)

(...)
49. LITERAL 0x22 ('"')
51. LITERAL 0x29 (')')
53. LITERAL 0x29 (')') # so expecting two brackets at the end, something is wrong!

To extract value, use group

match = re.search(p, my_str)
print(match.group(1))