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Created page with "UltraEdit supports Perl style regular expressions for search using the [http://www.boost.org/doc/libs/1_50_0/libs/regex/doc/html/boost_regex/syntax/perl_syntax.html Boost C++..."

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UltraEdit supports Perl style regular expressions for search using the [http://www.boost.org/doc/libs/1_50_0/libs/regex/doc/html/boost_regex/syntax/perl_syntax.html Boost C++ Libraries].

Note: in the following documentation, '''atom''' may refer to a single character, a marked sub-expression, or a character class.

In Perl regular expressions, all characters match themselves except for the following special characters:

{|
!Character
!Meaning
|-
|.
|Matches any single character except new lines
|-
|^
|Matches start of line (anchor)
|-
|$
|Matches end of line (anchor)
|-
|*
|Matches 0 or more of the preceding atom
|-
|<nowiki>+</nowiki>
|Matches 1 or more of the preceding atom
|-
|?
|Matches 0 or 1 of the preceding atom
|-
|<nowiki>[]</nowiki>
|Matches any character in the set. For example <nowiki>[a-d]</nowiki> would match a, b, c, and d – but not e.
|-
|()
|Tags the enclosed atom for backreferencing
|-
|{n}
|Matches the previous atom n times.
|-
|<nowiki>|</nowiki>
|"or" operand. For example <nowiki>dog|cat</nowiki> would match both "dog" and "cat."
|-
|\
|Escape character
|-
|}

'''Marked sub-expressions'''<br>
A section beginning ( and ending ) is a marked sub-expression. Whatever matched the sub-expression is split out in a separate field by the matching algorithms. Marked sub-expressions can also be repeated or referred to by a backreference.

'''Alternation'''<br>
The | operator will match either of its arguments, so for example: abc|def will match either "abc" or "def". Parenthesis can be used to group alternations, for example: ab(d|ef) will match either of "abd" or "abef". Empty alternatives are not allowed (these are almost always a mistake), but if you really want an empty alternative use (?:) as a placeholder, for example:

* "|abc" is not a valid expression, but
* "(?:)|abc" is and is equivalent, also the expression:
* "(?:abc)??" has exactly the same effect.

'''Character sets'''<br>
A character set is a bracket-expression starting with <nowiki>[ and ending with ]</nowiki>, it defines a set of characters, and matches any single character that is a member of that set.
A bracket expression may contain any combination of the following:
* '''Single characters:''' For example <nowiki>[abc]</nowiki>, will match any of the characters 'a', 'b', or 'c'.
* '''Character ranges:''' For example <nowiki>[a-c]</nowiki> will match any single character in the range 'a' to 'c'. By default, for POSIX-Perl regular expressions, a character x is within the range y to z, if it collates within that range; this results in locale specific behavior.
* '''Negation:''' If the bracket-expression begins with the ^ character, then it matches the complement of the characters it contains, for example <nowiki>[^a-c]</nowiki> matches any character that is not in the range a-c.
* '''Character classes:''' An expression of the form <nowiki>[[:name:]]</nowiki> matches the named character class "name", for example <nowiki>[[:lower:]]</nowiki> matches any lower case character.

'''Supported dcharacter class names''' (following the format <nowiki>[[:name:]]</nowiki>)<br>
{|
!Name
!POSIX-standard
!Description
|-
|alnum
|Yes
|Any alpha-numeric character.
|-
|alpha
|Yes
|Any alphabetic character.
|-
|blank
|Yes
|Any whitespace character that is not a line separator.
|-
|cntrl
|Yes
|Any control character.
|-
|d
|No
|Any decimal digit
|-
|digit
|Yes
|Any decimal digit.
|-
|graph
|Yes
|Any graphical character.
|-
|l
|No
|Any lower case character.
|-
|lower
|Yes
|Any lower case character.
|-
|print
|Yes
|Any printable character.
|-
|punct
|Yes
|Any punctuation character.
|-
|s
|No
|Any whitespace character.
|-
|space
|Yes
|Any whitespace character.
|-
|unicode
|No
|Any extended character whose code point is above 255 in value.
|-
|u
|No
|Any upper case character.
|-
|upper
|Yes
|Any upper case character.
|-
|w
|No
|Any word character (alphanumeric characters plus the underscore).
|-
|word
|No
|Any word character (alphanumeric characters plus the underscore).
|-
|xdigit
|Yes
|Any hexadecimal digit character.
|}

'''Escapes'''<br>
Any special character preceded by an escape matches itself. The following escape sequences are also supported (all synonyms for single characters):

{|
!Escape
!Character
|-
|\a
|'\a'
|-
|\e
|0x1B
|-
|\f
|\f
|-
|\n
|\n
|-
|\r
|\r
|-
|\t
|\t
|-
|\v
|\v
|-
|\b
|\b (but only inside a character class declaration).
|-
|\cX
|An ASCII escape sequence - the character whose code point is X % 32
|-
|\xdd
|A hexadecimal escape sequence - matches the single character whose code point is 0xdd.
|-
|\x{dddd}
|A hexadecimal escape sequence - matches the single character whose code point is 0xdddd.
|-
|\0ddd
|An octal escape sequence - matches the single character whose code point is 0ddd.
|-
|\N{name}
|Matches the single character which has the symbolic name name. For example \N{newline} matches the single character \n.
|}

'''"Single character" character classes'''<br>
Any escaped character x, if x is the name of a character class shall match any character that is a member of that class, and any escaped character X, if x is the name of a character class, shall match any character not in that class. The following are supported by default:

{|
!Escape sequence
!Equivalent to
|-
|\d
|<nowiki>[[:digit:]]</nowiki>
|-
|\l
|<nowiki>[[:lower:]]</nowiki>
|-
|\s
|<nowiki>[[:space:]]</nowiki>
|-
|\u
|<nowiki>[[:upper:]]</nowiki>
|-
|\w
|<nowiki>[[:word:]]</nowiki>
|-
|\D
|<nowiki>[^[:digit:]]</nowiki>
|-
|\L
|<nowiki>[^[:lower:]]</nowiki>
|-
|\S
|<nowiki>[^[:space:]]</nowiki>
|-
|\U
|<nowiki>[^[:upper:]]</nowiki>
|-
|\W
|<nowiki>[^[:word:]]</nowiki>
|}

'''Word Boundaries'''<br>
The following escape sequences match the boundaries of words:

{|
|\<
|Matches the start of a word.
|-
|\>
|Matches the end of a word.
|-
|\b
|Matches a word boundary (the start or end of a word).
|-
|\B
|Matches only when not at a word boundary.
|}

For further information options on Perl regular please see:
* [http://www.boost.org/doc/libs/1_50_0/libs/regex/doc/html/boost_regex/syntax/perl_syntax.html Boost C++ Libraries documentation]
* [https://www.ultraedit.com/support/tutorials-power-tips/ultraedit/perl-regular-expressions.html Perl regular expressions: getting started (power tip)]
* [https://www.ultraedit.com/support/tutorials-power-tips/ultraedit/perl-regular-expressions-digging-deeper.html Perl regular expressions: digging deeper (power tip)]
* [https://www.ultraedit.com/support/tutorials-power-tips/ultraedit/non-greedy-perl-regex.html Perl regular expressions: non-greedy regex (power tip)]
* [https://www.ultraedit.com/support/tutorials-power-tips/ultraedit/perl-regular-expressions-backreferences.html Perl regular expressions: backreferences (power tip)]

<div class="idm-see-also">
See also:
* [[Regular expressions]]
</div>

@@ Line 232: / Line 232: @@
 |}
-'''Word Boundaries'''<br>
+'''Assertions'''<br>
-The following escape sequences match the boundaries of words:
+Besides ^ and $ , Perl regular expressions support the following zero-width assertions:
 {|
@@ Line 247: / Line 247: @@
 |\B
 |Matches only when not at a word boundary.
 |}

@@ Line 259: / Line 259: @@
 See also:
 * [[Regular expressions]]
-* [[Special_search_characters]]
+* [[Special search characters]]
 </div>

@@ Line 245: / Line 245: @@
 |Matches a word boundary (the start or end of a word).
 |-
-<code><nowiki>|\B</nowiki></code>
+|<code>\B</code>
 |Matches only when not at a word boundary.
 |-

Perl regular expressions - Revision history

Idmadmin at 19:10, 7 June 2018

Idmadmin at 19:09, 7 June 2018

Idmadmin at 15:35, 26 October 2017

Idmadmin at 13:30, 10 August 2017

Idmadmin at 13:30, 10 August 2017

Idmadmin: Created page with "UltraEdit supports Perl style regular expressions for search using the [http://www.boost.org/doc/libs/1_50_0/libs/regex/doc/html/boost_regex/syntax/perl_syntax.html Boost C++..."