I am completely new to writing regular expressions. I am trying to write a Regex that will not allow the following terms in a text box.
the The T h e
views:
64answers:
4
+1
A:
/t ?h ?e/i will match any of the variations above (and others such as T hE).
How you reject input that matches this pattern depends on the language and libraries you are using.
Sinan Ünür
2010-02-12 18:19:37
A:
It depends what language you are using, but you can specify case-insensitivity.
if you want a regex that checks to see if it exists try:
(the|t\sh\se)
Roo
2010-02-12 18:19:50
That character class is not doing what you think it is doing.
Sinan Ünür
2010-02-12 18:21:50
Your second expression won’t work. `[^(the|t\sh\se)]` means *one characters except `(`, `t`, `h`, `e`, `|`, `\s`, `)`*.
Gumbo
2010-02-12 18:22:20
good catch! thanks!
Roo
2010-02-12 18:30:02
A:
I recommend using http://www.regular-expressions.info they have a very good quickstart guide and a very through tutorial. It helped me a lot when I first was learning Regular expressions.
Scott Chamberlain
2010-02-12 18:26:25
+3
A:
If you want to match on things like 'WHAT H ELL' then simply rip all the whitespace from the string so you get 'WHATHELL' and then look for 'THE'
If you don't include those situations, then use this regex with case sensitivity turned off
\bt\s*h\s*e\b
result
WHAT H E - fail
The - success
T he - success
th E - success
t h e - success
the - success
them - fail
hasthem - fail
has them - fail
Chad
2010-02-12 18:29:31
Chad your solution works good however i think its the editor problem, i think you actually said "t\s*h\s*e" and i think the /b and \b were appended because of the editor. So "t\s*h\s*e" is the answer...
2010-02-12 19:51:41
No, I added the \b\b as they are word boundaries. To differentiate "This is the sentence." having the word 'the' from, the sentence "I'll go with them too." with the word 'them' Without the \b around the phrase, it will match on the word 'them'.This is why you should download and use expresso to write and test regexes.
Chad
2010-02-12 20:00:17
new Regex("\\bt\\s*h\\s*e\\b", RegexOptions.IgnoreCase | RegexOptions.CultureInvariant | RegexOptions.Compiled);
Chad
2010-02-12 21:57:00