this post was submitted on 23 Jul 2025
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How so? I have been getting much more comfortable with it lately, but I am curious what downsides there are
The downsides are having to relearn it every time you need to understand it.
Just use something like https://regex101.com/
not really i just meant they suck to remember how to write without looking up :)
Here is my cheatsheet that has been very helpful. Obviously, this will not teach you how RegEx works, but is a good quick reference when I forget the exact syntax for something.
RegExp
Character classes
.
\w
\d
\s
\W
\D
\S
[abc]
[a-e]
a
ande
[1-9]
1
and9
[[:print:]]
[^abc]
a
,b
orc
Anchors
\G
^
$
\A
\Z
\z
\b
\B
^abc
abc
abc$
abc
For multiline patterns (
m
flag),^
and$
will act as start and end of line.Escaped characters
\. \* \\
\t
\n
\r
Groups
(abc)
(a|b)
a
orb
(?:abc)
abc
, but don't capture\1
Quantifiers
a*
a+
a?
a{5}
a{,3}
a{3,}
a{1,3}
Lookahead & Lookbehind
| Pattern | Description | |
|
a(?=b)
| Matcha
inbaby
but not inbay
| |a(?!b)
| Matcha
inStan
but not inStab
| |(?<=a)b
| Matchb
incrabs
but not incribs
| |(?<!a)b
| Matchb
infib
but not infab
| |(?<![a-z])abc(?![a-z])
| Matchabc
without any letters before/after |Raw Markdown