How to match a whole word that includes special characters in regex

Question

In regex is there a way to escape special characters in an entire region of text in PCRE syntax?

eg. hey+Im+A+Single+Word+Including+The+Pluses+And.Dots

Normally to match the exact string in regex I would have to escape every single + and . with /s in the above string. This means that if the string is a variable, One has to seek for special characters and escape them manually. Is there an easier way to do this by telling regex escape all special characters in a block of text?

The motivation behind this is to append this to a larger regex so even though there are easier ways to get exact matches they don't apply here.

Possible duplicate of [Is there a RegExp.escape function in Javascript?](http://stackoverflow.com/questions/3561493/is-there-a-regexp-escape-function-in-javascript) — Linus Thiel, Dec 17 '15 at 21:03
It may be worth noting that when using sed without extended regex (-r flag), `+` aren't recognized as meta-characters — Aaron, Dec 17 '15 at 21:11
It is R but syntax is perl. @revo's answer is what I was looking for — OganM, Dec 17 '15 at 22:03
The syntax is exactly PCRE, `perl` is only the attribute name that can be used in Base R grep functions. — Wiktor Stribiżew, Dec 17 '15 at 22:12

revo · Accepted Answer · 2015-12-17T21:16:40.277

5

Everything between \Q and \E meta characters are treated as literals in PERL Compatible RegExes (PCRE). So in your case:

\Qhey+Im+A+Single+Word+Including+The+Pluses+And.Dots\E

Other engines rarely support this syntax.

edited Dec 17 '15 at 21:16

answered Dec 17 '15 at 21:03

revo

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Java's `Pattern` class also supports the `\Q…\E` syntax. – mistercake Dec 17 '15 at 21:08

score 1 · Answer 2 · answered Feb 12 '18 at 03:37

If it's python. you can use re.escape(string) to get a literals string

import re

search = 'hey+Im+A+Single+Word+Including+The+Pluses+And.Dots'
text = '''hey+Im+A+Single+Word+Including+The+Pluses+And.Dots 
heyImmASingleWordIncludingThePlusessAndaDots 
heyImASingleWordIncludingThePlusesAndxDots 
'''
rc = re.escape(search)
#exactly first line in text
print(re.findall(rc,text))

#line two and three as it will + as repeat and . as any char
print(re.findall(search,text))

-------- result -------------------

['hey+Im+A+Single+Word+Including+The+Pluses+And.Dots'] ['heyImmASingleWordIncludingThePlusessAndaDots', 'heyImASingleWordIncludingThePlusesAndxDots']

How to match a whole word that includes special characters in regex

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