battle programmers alliance
Would you like to react to this message? Create an account in a few clicks or log in to continue.

battle programmers allianceLog in

the LivinGrimoire Artificial General Intelligence software design pattern forum

descriptionregex grimoire Emptyregex grimoire

list of all quantifiers:

a|b– Match either “a” or “b
? – Zero or one
+ – one or more
* – zero or more
{N} – Exactly N number of times (where N is a number)
{N,} – N or more number of times (where N is a number)
{N,M} – Between N and M number of times (where N and M are numbers and N < M)
*? – Zero or more, but stop after first match
. : any char

Hi+ will also match with Hiiiiiiiiiiiiiiiiiiiiii

common pattern collections:

[A-Z]– Match any uppercase character from “A” to “Z”
[a-z]– Match any lowercase character from “a” to “z”
[0-9] – Match any number
[asdf]– Match any character that’s either “a”, “s”, “d”, or “f”
[^asdf]– Match any character that’s not any of the following: “a”, “s”, “d”, or “f”

You can even combine these together:

[0-9A-Z]– Match any character that’s either a number or a capital letter from “A” to “Z”
[^a-z] – Match any non-lowercase letter

general token:

. – Any character
\n – Newline character
\t – Tab character
\s– Any whitespace character (including \t, \n and a few others)
\S – Any non-whitespace character
\w– Any word character (Uppercase and lowercase Latin alphabet, numbers 0-9, and _)
\W– Any non-word character (the inverse of the \w token)
\b– Word boundary: The boundaries between \w and \W, but matches in-between characters
\B– Non-word boundary: The inverse of \b
^ – The start of a line
$ – The end of a line
\– The literal character “\”

\s. will match with any white space and 1st char after it:
Hello world how are you -> Helloorldowreou

Combining with collections
These tokens aren’t just useful on their own, though! Let’s say that we want to remove any uppercase letter or whitespace character. Sure, we could write

But we can actually merge these together and place our \s token into the collection:


^\w+ first word
\w+$ last word

character escape:
using\. This means that your regex might look something like this:


regex group example:
(Testing|tests) 123
will match : Testing 123 or tests 123

Lookahead and lookbehind groups

(?!) – negative lookahead
(?=) – positive lookahead
(?<=) – positive lookbehind
(?<!) – negative lookbehind
B(?!A) will match the B in BC but not BA
^(?!Test).*$ will match any string that doesn't start with Test

descriptionregex grimoire EmptyRe: regex grimoire

RegexUtil class for utilizing regex easily :





smell you later

privacy_tip Permissions in this forum:
You cannot reply to topics in this forum
power_settings_newLogin to reply