PCRE cheatsheet attempt
|
(?=...)
|
Positive Lookahead
|
question(?=s)
|
questions
|
question
|
|
(?!...)
|
Negative Lookahead
|
answer(?!s)
|
answer
|
answers
|
|
(?<=...)
|
Positive Lookbehind
|
(?<=appl)e
|
apple
|
application
|
|
(?<!...)
|
Negative Lookbehind
|
(?<!goo)d
|
mood
|
good
|
|
(?(condition)...)
|
if-then pattern
|
(<)?p(?(1)>)
|
<p>, p
|
<p
|
|
(?(condition)...|...)
|
if-then-else pattern
|
^(?(?=q)que|ans)
|
question, answer
|
quote
|
|
^
|
Start of string or line
|
|
$
|
End of string, or end of line in multi-line pattern
|
|
\A
|
Start of string, ignores m flag
|
|
\z
|
End of string, ignores m flag
|
|
\Z
|
End of string or char before last new line, ignores m flag
|
|
\b
|
Word boundary; position between a word character (\w), and a nonword character (\W)
|
|
\B
|
Not word boundary
|
|
\G
|
End of the previous match or the start of the string for the first match
|
|
g
|
Global match
|
|
i
|
Ignore case
|
|
m
|
Multiple lines (^ and $ match start and end of a line)
|
|
s
|
Single line (. matches newline)
|
|
x
|
Specifies that whitespace characters in the pattern are ignored except when escaped or inside a character class
|
|
J
|
Duplicate group names allowed
|
|
U
|
Ungreedy quantifiers
|
|
A
|
Anchored, the pattern is forced to match only at the beginning (^)
|
|
E
|
Anchored, the pattern is forced to match only at the end ($)
|
|
a|b
|
a or b
|
|
+
|
1 or more
|
|
*
|
0 or more
|
|
?
|
0 or 1
|
|
??
|
0 or 1, as few times as possible (lazy)
|
|
+?
|
1 or more, as few times as possible (lazy)
|
|
*?
|
0 or more, as few times as possible (lazy)
|
|
{n}
|
n times exactly
|
|
{n,m}
|
From n to m times
|
|
{n,}
|
At least n time
|
|
(...)
|
Capturing
|
|
(?P<obj>...)
|
Capturing group named "obj"
|
|
(?P=obj)
|
Match the named group "obj"
|
|
\g{Z}
|
Match the named or numbered group Z
|
|
\Y
|
Match the Y'th captured group
|
|
(?>...)
|
Atomic group: This group does not allow any backtracking to occur
|
|
(?|...)
|
Duplicate group numbers
|
|
(?#...)
|
Comment between parenthesis
|
|
(?:...)
|
Matches but does not capture the group
|
|
(?&obj)
|
Recurse into the named group "obj"
|
|
(?Y)
|
Recurse into numbered group Y
|
|
(?R)
|
Recurse into entire pattern
|
|
\g<Z>
|
Recurse into the named or numbered group Z
|
|
.
|
Any character except new line (\n)
|
|
[abc-f]
|
One character of: a, b, c, d, e, f
|
|
[^abc-f]
|
One character except: a, b, c, d, e, f
|
|
\d
|
One digit
|
|
\D
|
One non-digit
|
|
\s
|
One whitespace
|
|
\S
|
One non-whitespace
|
|
\w
|
One word [a-zA-Z0-9_]
|
|
\W
|
One non-word [^a-zA-Z0-9_]
|
|
\\
|
General Escape
|
|
\n
|
New line or line feed
|
|
\r
|
Carriage return (used to reset a device's position to the beginning of a line of text)
|
|
\t
|
Tab
|
|
\0
|
Null character
|
|
\xHH
|
Hexademical digit HH
|
|
\oOOO
|
Octal digit OOO
|
|
[\b]
|
Backspace (yes it's inside brackets)
|
|
\f
|
Form feed (next page)
|
|
\v
|
Vertical tab
|
|
\Q...\E
|
Remove special meaning from a sequence of characters
|
|
[:xdigit:]
|
Hexadecimal digits
|
|
[:upper:]
|
Uppercase letters
|
|
[:lower:]
|
Lowercase letters
|
|
[:alpha:]
|
Letters
|
|
[:alnum:]
|
Letters and digits
|
|
[:ascii:]
|
Ascii codes 0 - 127
|
|
[:cntrl:]
|
Control characters
|
|
[:print:]
|
Visible characters
|
|
[:punct:]
|
Visible punctuation characters
|
No comments yet.
Cheatography n. The art of mapping complex subjects into clear, instantly navigable reference guides.
