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Quick TrainerRegular Expression Tokens and Their Meanings
Master what each common regular-expression token, anchor, and metacharacter matches.
Code37 items4 levelsDifficulty 3/5
Free · no signup · works on any device
Levels
Start easy — harder levels unlock as you improve, or jump ahead anytime.
1
Basics
9 items
2
Quantifiers & Anchors
10 items
3
Classes & Groups
9 items
4
Advanced
9 items
All 37 cards
.
any single character (except newline)
\d
any digit (0-9)
\D
any non-digit
\w
any word character (letter, digit, underscore)
\W
any non-word character
\s
any whitespace character
\S
any non-whitespace character
\n
newline
\t
tab
*
zero or more of the preceding
+
one or more of the preceding
?
zero or one of the preceding (optional)
{n}
exactly n of the preceding
{n,}
n or more of the preceding
{n,m}
between n and m of the preceding
^
start of string or line
$
end of string or line
\b
word boundary
\B
non-word boundary
[abc]
any one of a, b, or c
[^abc]
any character except a, b, or c
[a-z]
any lowercase letter a through z
[0-9]
any digit 0 through 9
|
alternation (or)
(abc)
capturing group
(?:abc)
non-capturing group
\1
backreference to group 1
\.
a literal dot
(?=abc)
positive lookahead
(?!abc)
negative lookahead
(?<=abc)
positive lookbehind
(?<!abc)
negative lookbehind
*?
lazy zero or more (non-greedy)
+?
lazy one or more (non-greedy)
(?<name>abc)
named capturing group
\A
start of string only
\Z
end of string only
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