Talk:Regular expression examples/sandbox
Trying to come up with a language-independent version of this article...
| Metacharacter(s) | Description | Example | |||
|---|---|---|---|---|---|
| string | regex | match | notes | ||
.
|
Normally matches any character except a newline. Within square brackets the
dot is literal |
Hello World
|
......
|
Hello,
|
|
( )
|
Groups a series of pattern elements to a single element. [1] | Hello World
|
(H..).(o..)
|
Hello WGroup 1: |
|
?
|
Matches the preceding pattern element zero or one times. | Hello World
|
H(.?)e
|
He Group 1: |
There is a possible character (no, in this case) between 'H' and 'e'. |
+
|
Matches the preceding pattern element one or more times. | Hello World
|
l+
|
ll
|
There are one or more consecutive letter "l"'s in "Hello World" |
*
|
Matches the preceding pattern element zero or more times. | Hello World
|
el*o
|
ello
|
There is an 'e' followed by zero to many 'l' followed by 'o' (eo, elo, ello, elllo) |
{M,N}
|
Denotes the minimum M and the maximum N match count. | Hello World
|
l{1,2}
|
ll |
There exists a substring with at least 1 and at most 2 l's |
?
|
Modifies the *, +, or {M,N}'d regexp that comes before
to match as few times as possible. |
Hello World
|
l+?
|
l
|
Compare this (called the non-greedy match) with the greedier version
above with the unmodified '+'. |
[...]
|
Denotes a set of possible character matches. | Hello World
|
[aeiou]+
|
e |
Matches the first occurrence of a succession of vowels (one or more). |
[^...]
|
Matches every character except the ones inside brackets. | Hello World
|
[^aeiou]+
|
H
|
Matches the first occurrence of a succession of 'not-vowels' |
| Separates alternate possibilities. | Hello World
|
Hi|Pogo) | Hello
|
At least one of Hello, Hi, or Pogo is contained in the string. | |
\b
|
Matches a word boundary | Hello World
|
ell\b
|
matches nothing | There is no substring matching 'ell' at the end of a word |
\w
|
Matches a 'word' character (defined as the group of alphanumeric
characters, including the underscore "_"; same as |
Hello World
|
\w
|
H |
There is at least one alphanumeric character in string
(A-Z, a-z, 0-9, _) |
\W
|
Matches a non-alphanumeric character, excluding "_"; same as [^A-Za-z0-9_] | Hello World
|
\W
|
«space» | The space between Hello and World is not alphanumeric |
\s
|
Matches a whitespace character (space, tab, newline, form feed) | Hello World
|
\s.*
|
World
|
Any characters (0 or more) after a whitespace character |
\S
|
Matches anything BUT a whitespace. | Hello World
|
\S.*\S
|
Hello World
|
There are TWO non-whitespace characters, which may be separated
by other characters |
\d
|
Matches a digit; same as [0-9]. | 99 bottles of beer on the wall
|
(\d+)
|
Group 1: 99
|
Group 1 is the first number in the string |
\D
|
Matches a non-digit; same as [^0-9]. | 99 bottles of beer on the wall
|
\D
|
«space» | The first non-digit character is the space after 99 |
^
|
Matches the beginning of a line or string. | Hello World
|
^He
|
He
|
The string starts with the characters 'He' |
$
|
Matches the end of a line or string. | Hello World
|
rld$
|
rld
|
The given string is a line or string that ends with 'rld' |
\A
|
Matches the beginning of a string (but not an internal line). | Hello\nWorld
|
\AH
|
H
|
The matched string starts with 'H' |
\z
|
Matches the end of a string (but not an internal line). | Hello\nWorld\n
|
d\n\z
|
d\n
|
The matched string is a string that ends with 'd\\n' |