$var !~ /foo/;
-C<m/pattern/msixpogc> searches a string for a pattern match,
+C<m/pattern/msixpogcdualn> searches a string for a pattern match,
applying the given options.
m Multiline mode - ^ and $ match internal lines
o compile pattern Once
g Global - all occurrences
c don't reset pos on failed matches when using /g
+ a restrict \d, \s, \w and [:posix:] to match ASCII only
+ aa (two a's) also /i matches exclude ASCII/non-ASCII
+ l match according to current locale
+ u match according to Unicode rules
+ d match according to native rules unless something indicates
+ Unicode
+ n Non-capture mode. Don't let () fill in $1, $2, etc...
If 'pattern' is an empty string, the last I<successfully> matched
regex is used. Delimiters other than '/' may be used for both this
operator and the following ones. The leading C<m> can be omitted
if the delimiter is '/'.
-C<qr/pattern/msixpo> lets you store a regex in a variable,
+C<qr/pattern/msixpodualn> lets you store a regex in a variable,
or pass one around. Modifiers as for C<m//>, and are stored
within the regex.
-C<s/pattern/replacement/msixpogce> substitutes matches of
+C<s/pattern/replacement/msixpogcedual> substitutes matches of
'pattern' with 'replacement'. Modifiers as for C<m//>,
with two additions:
(...) Groups subexpressions for capturing to $1, $2...
(?:...) Groups subexpressions without capturing (cluster)
| Matches either the subexpression preceding or following it
- \1, \2, \3 ... Matches the text from the Nth group
\g1 or \g{1}, \g2 ... Matches the text from the Nth group
+ \1, \2, \3 ... Matches the text from the Nth group
\g-1 or \g{-1}, \g-2 ... Matches the text from the Nth previous group
\g{name} Named backreference
\k<name> Named backreference
\n Newline
\r Carriage return
\t Tab
- \037 Any octal ASCII value
- \x7f Any hexadecimal ASCII value
- \x{263a} A wide hexadecimal value
+ \037 Char whose ordinal is the 3 octal digits, max \777
+ \o{2307} Char whose ordinal is the octal number, unrestricted
+ \x7f Char whose ordinal is the 2 hex digits, max \xFF
+ \x{263a} Char whose ordinal is the hex number, unrestricted
\cx Control-x
- \N{name} A named character
+ \N{name} A named Unicode character or character sequence
\N{U+263D} A Unicode character by hex ordinal
\l Lowercase next character
\u Titlecase next character
\L Lowercase until \E
\U Uppercase until \E
+ \F Foldcase until \E
\Q Disable pattern metacharacters until \E
\E End modification
\S A non-whitespace character
\h An horizontal whitespace
\H A non horizontal whitespace
- \N A non newline (when not followed by '{NAME}'; experimental;
+ \N A non newline (when not followed by '{NAME}';;
not valid in a character class; equivalent to [^\n]; it's
like '.' without /s modifier)
\v A vertical whitespace
\V A non vertical whitespace
\R A generic newline (?>\v|\x0D\x0A)
- \C Match a byte (with Unicode, '.' matches a character)
\pP Match P-named (Unicode) property
\p{...} Match Unicode property with name longer than 1 character
\PP Match non-P
POSIX character classes and their Unicode and Perl equivalents:
- ASCII- Full-
- range range backslash
- POSIX \p{...} \p{} sequence Description
+ ASCII- Full-
+ POSIX range range backslash
+ [[:...:]] \p{...} \p{...} sequence Description
+
-----------------------------------------------------------------------
- alnum PosixAlnum Alnum Alpha plus Digit
- alpha PosixAlpha Alpha Alphabetic characters
- ascii ASCII Any ASCII character
- blank PosixBlank Blank \h Horizontal whitespace;
- full-range also written
- as \p{HorizSpace} (GNU
- extension)
- cntrl PosixCntrl Cntrl Control characters
- digit PosixDigit Digit \d Decimal digits
- graph PosixGraph Graph Alnum plus Punct
- lower PosixLower Lower Lowercase characters
- print PosixPrint Print Graph plus Print, but not
- any Cntrls
- punct PosixPunct Punct These aren't precisely
- equivalent. See NOTE,
- below.
- space PosixSpace Space [\s\cK] Whitespace
- PerlSpace SpacePerl \s Perl's whitespace
- definition
- upper PosixUpper Upper Uppercase characters
- word PerlWord Word \w Alnum plus '_' (Perl
- extension)
- xdigit ASCII_Hex_Digit XDigit Hexadecimal digit,
- ASCII-range is
- [0-9A-Fa-f]
-
-NOTE on C<[[:punct:]]>, C<\p{PosixPunct}> and C<\p{Punct}>:
-In the ASCII range, C<[[:punct:]]> and C<\p{PosixPunct}> match
-C<[-!"#$%&'()*+,./:;<=E<gt>?@[\\\]^_`{|}~]> (although if a locale is in
-effect, it could alter the behavior of C<[[:punct:]]>); and C<\p{Punct}>
-matches C<[-!"#%&'()*,./:;?@[\\\]_{}]>. When matching a UTF-8 string,
-C<[[:punct:]]> matches what it does in the ASCII range, plus what
-C<\p{Punct}> matches. C<\p{Punct}> matches, anything that isn't a
-control, an alphanumeric, a space, nor a symbol.
+ alnum PosixAlnum XPosixAlnum 'alpha' plus 'digit'
+ alpha PosixAlpha XPosixAlpha Alphabetic characters
+ ascii ASCII Any ASCII character
+ blank PosixBlank XPosixBlank \h Horizontal whitespace;
+ full-range also
+ written as
+ \p{HorizSpace} (GNU
+ extension)
+ cntrl PosixCntrl XPosixCntrl Control characters
+ digit PosixDigit XPosixDigit \d Decimal digits
+ graph PosixGraph XPosixGraph 'alnum' plus 'punct'
+ lower PosixLower XPosixLower Lowercase characters
+ print PosixPrint XPosixPrint 'graph' plus 'space',
+ but not any Controls
+ punct PosixPunct XPosixPunct Punctuation and Symbols
+ in ASCII-range; just
+ punct outside it
+ space PosixSpace XPosixSpace \s Whitespace
+ upper PosixUpper XPosixUpper Uppercase characters
+ word PosixWord XPosixWord \w 'alnum' + Unicode marks
+ + connectors, like
+ '_' (Perl extension)
+ xdigit ASCII_Hex_Digit XPosixDigit Hexadecimal digit,
+ ASCII-range is
+ [0-9A-Fa-f]
+
+Also, various synonyms like C<\p{Alpha}> for C<\p{XPosixAlpha}>; all listed
+in L<perluniprops/Properties accessible through \p{} and \P{}>
Within a character class:
^ Match string start (or line, if /m is used)
$ Match string end (or line, if /m is used) or before newline
+ \b{} Match boundary of type specified within the braces
+ \B{} Match wherever \b{} doesn't match
\b Match word boundary (between \w and \W)
\B Match except at word boundary (between \w and \w or \W and \W)
\A Match string start (regardless of /m)
(?<name>...) Named capture
(?'name'...) Named capture
(?P<name>...) Named capture (python syntax)
+ (?[...]) Extended bracketed character class
(?{ code }) Embedded code, return value becomes $^R
(??{ code }) Dynamic regex, return value used as regex
(?N) Recurse into subpattern number N
(?P>name) Recurse into a named subpattern (python syntax)
(?(cond)yes|no)
(?(cond)yes) Conditional expression, where "cond" can be:
+ (?=pat) lookahead
+ (?!pat) negative lookahead
+ (?<=pat) lookbehind
+ (?<!pat) negative lookbehind
(N) subpattern N has matched something
(<name>) named subpattern has matched something
('name') named subpattern has matched something
${^MATCH} Entire matched string
${^POSTMATCH} Everything after to matched string
+Note to those still using Perl 5.18 or earlier:
The use of C<$`>, C<$&> or C<$'> will slow down B<all> regex use
within your program. Consult L<perlvar> for C<@->
to see equivalent expressions that won't cause slow down.
can also use the equivalent variables C<${^PREMATCH}>, C<${^MATCH}>
and C<${^POSTMATCH}>, but for them to be defined, you have to
specify the C</p> (preserve) modifier on your regular expression.
+In Perl 5.20, the use of C<$`>, C<$&> and C<$'> makes no speed difference.
$1, $2 ... hold the Xth captured expr
$+ Last parenthesized pattern match
$^R Holds the result of the last (?{...}) expr
@- Offsets of starts of groups. $-[0] holds start of whole match
@+ Offsets of ends of groups. $+[0] holds end of whole match
- %+ Named capture buffers
- %- Named capture buffers, as array refs
+ %+ Named capture groups
+ %- Named capture groups, as array refs
Captured groups are numbered according to their I<opening> paren.
lcfirst Lowercase first char of a string
uc Uppercase a string
ucfirst Titlecase first char of a string
+ fc Foldcase a string
pos Return or set current match position
quotemeta Quote metacharacters
split Use a regex to split a string into parts
-The first four of these are like the escape sequences C<\L>, C<\l>,
-C<\U>, and C<\u>. For Titlecase, see L</Titlecase>.
+The first five of these are like the escape sequences C<\L>, C<\l>,
+C<\U>, C<\u>, and C<\F>. For Titlecase, see L</Titlecase>; For
+Foldcase, see L</Foldcase>.
=head2 TERMINOLOGY
Unicode concept which most often is equal to uppercase, but for
certain characters like the German "sharp s" there is a difference.
+=head3 Foldcase
+
+Unicode form that is useful when comparing strings regardless of case,
+as certain characters have complex one-to-many case mappings. Primarily a
+variant of lowercase.
+
=head1 AUTHOR
Iain Truskett. Updated by the Perl 5 Porters.
=item *
-L<perldebug/"Debugging regular expressions">
+L<perldebug/"Debugging Regular Expressions">
=item *
https://perl5.git.perl.org / perl5.git / blobdiff