Rectangle 27 1

Reference What does this regex mean?


$1
(*BSR_ANYCRLF)
(*F)
(*FAIL)
(*PRUNE)
(*SKIP)
(...)
(?!...)
(?:)
(?<!...)
(?<=...)
(?<groupname>regex)
(?=...)
(?>)
(?P<group_name>regexp)
(?P<groupname>regex)
(?|)
*+
*?
++
+?
Matcher
[...]
[.]
[[:alpha:]]
[\w&&[^\d]]
[\w-[\d]]
[^...]
[^2[^0-9]]
[^[^0-9]2]
[^\\D2]
[^]
[a-z-[qz]]
\1
\B
\D
\G
\H
\K
\S
\V
\W
\b
\d
\e
\h
\p{L}, \P{L}
\s
\t
\v
\w
freeformatter.com
java.util.regex.Matcher
lookingAt()
match
matches()
preg_match
regex.larsolavtorvik.com
regexp
search
{0,n}
{n,m}
{n,}
{n}

Examples of regex that can cause regex engine to fail

  • Debuggex (Also has a repository of useful regexes) javascript, python, pcre
  • Recursion (php and perl): (?R), (?0) and (?1), (?-1), (?&groupname)
  • Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems. (blog post written by Stack Overflow's founder)*
  • The only java.lang.String functions that accept regular expressions: matches(s), replaceAll(s,s), replaceFirst(s,s), split(s), split(s,i)
  • find()): A match may be anywhere in the input string (substrings)

@Wildcard - This page is/should definitely be for comment linking after some introductory, general info. But, I've seen it used inappropriately as a direct duplicate too many times.

@sln A rare example of when you should shoot the messenger.

@sln, I think the correct usage would be to look up the answer to a newly asked regex question in this reference, find the linked Q&A that really does answer the new question and is a dupe, mark the new question as a dupe of that post, and add a comment linking to this page.

I don't understand this treatise. While it is (and has) a functional value and good links, nobody that is a beginner will ever understand anything past the first line. Therefore it is useless as an instructional tool. It's title Reference - What does this regex mean? does not tell you what any particular regex means. It is a mish-mash of links.. an overwhelming blend if you will, of the universe of regex constructs from different engines. To make things worse, some people mark regex questions as a direct duplicate of this question. It's sad ..

Note
Rectangle 27 1

Reference What does this regex mean?


$1
(*BSR_ANYCRLF)
(*F)
(*FAIL)
(*PRUNE)
(*SKIP)
(...)
(?!...)
(?:)
(?<!...)
(?<=...)
(?<groupname>regex)
(?=...)
(?>)
(?P<group_name>regexp)
(?P<groupname>regex)
(?|)
*+
*?
++
+?
Matcher
[...]
[.]
[[:alpha:]]
[\w&&[^\d]]
[\w-[\d]]
[^...]
[^2[^0-9]]
[^[^0-9]2]
[^\\D2]
[^]
[a-z-[qz]]
\1
\B
\D
\G
\H
\K
\S
\V
\W
\b
\d
\e
\h
\p{L}, \P{L}
\s
\t
\v
\w
freeformatter.com
java.util.regex.Matcher
lookingAt()
match
matches()
preg_match
regex.larsolavtorvik.com
regexp
search
{0,n}
{n,m}
{n,}
{n}

Examples of regex that can cause regex engine to fail

  • Debuggex (Also has a repository of useful regexes) javascript, python, pcre
  • Recursion (php and perl): (?R), (?0) and (?1), (?-1), (?&groupname)
  • Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems. (blog post written by Stack Overflow's founder)*
  • The only java.lang.String functions that accept regular expressions: matches(s), replaceAll(s,s), replaceFirst(s,s), split(s), split(s,i)
  • find()): A match may be anywhere in the input string (substrings)

@Wildcard - This page is/should definitely be for comment linking after some introductory, general info. But, I've seen it used inappropriately as a direct duplicate too many times.

@sln A rare example of when you should shoot the messenger.

@sln, I think the correct usage would be to look up the answer to a newly asked regex question in this reference, find the linked Q&A that really does answer the new question and is a dupe, mark the new question as a dupe of that post, and add a comment linking to this page.

I don't understand this treatise. While it is (and has) a functional value and good links, nobody that is a beginner will ever understand anything past the first line. Therefore it is useless as an instructional tool. It's title Reference - What does this regex mean? does not tell you what any particular regex means. It is a mish-mash of links.. an overwhelming blend if you will, of the universe of regex constructs from different engines. To make things worse, some people mark regex questions as a direct duplicate of this question. It's sad ..

Note
Rectangle 27 0

Reference What does this regex mean?


$1
(*BSR_ANYCRLF)
(*F)
(*FAIL)
(*PRUNE)
(*SKIP)
(...)
(?!...)
(?:)
(?<!...)
(?<=...)
(?<groupname>regex)
(?=...)
(?>)
(?P<group_name>regexp)
(?P<groupname>regex)
(?|)
*+
*?
++
+?
Matcher
[...]
[.]
[[:alpha:]]
[\w&&[^\d]]
[\w-[\d]]
[^...]
[^2[^0-9]]
[^[^0-9]2]
[^\\D2]
[^]
[a-z-[qz]]
\1
\B
\D
\G
\H
\K
\S
\V
\W
\b
\d
\e
\h
\p{L}, \P{L}
\s
\t
\v
\w
freeformatter.com
java.util.regex.Matcher
lookingAt()
match
matches()
preg_match
regex.larsolavtorvik.com
regexp
search
{0,n}
{n,m}
{n,}
{n}

Examples of regex that can cause regex engine to fail

  • Debuggex (Also has a repository of useful regexes) javascript, python, pcre
  • Recursion (php and perl): (?R), (?0) and (?1), (?-1), (?&groupname)
  • Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems. (blog post written by Stack Overflow's founder)*
  • The only java.lang.String functions that accept regular expressions: matches(s), replaceAll(s,s), replaceFirst(s,s), split(s), split(s,i)
  • find()): A match may be anywhere in the input string (substrings)

@Wildcard - This page is/should definitely be for comment linking after some introductory, general info. But, I've seen it used inappropriately as a direct duplicate too many times.

@sln A rare example of when you should shoot the messenger.

@sln, I think the correct usage would be to look up the answer to a newly asked regex question in this reference, find the linked Q&A that really does answer the new question and is a dupe, mark the new question as a dupe of that post, and add a comment linking to this page.

I don't understand this treatise. While it is (and has) a functional value and good links, nobody that is a beginner will ever understand anything past the first line. Therefore it is useless as an instructional tool. It's title Reference - What does this regex mean? does not tell you what any particular regex means. It is a mish-mash of links.. an overwhelming blend if you will, of the universe of regex constructs from different engines. To make things worse, some people mark regex questions as a direct duplicate of this question. It's sad ..

Note
Rectangle 27 0

Reference What does this regex mean?


$1
(*BSR_ANYCRLF)
(*F)
(*FAIL)
(*PRUNE)
(*SKIP)
(...)
(?!...)
(?:)
(?<!...)
(?<=...)
(?<groupname>regex)
(?=...)
(?>)
(?P<group_name>regexp)
(?P<groupname>regex)
(?|)
*+
*?
++
+?
Matcher
[...]
[.]
[[:alpha:]]
[\w&&[^\d]]
[\w-[\d]]
[^...]
[^2[^0-9]]
[^[^0-9]2]
[^\\D2]
[^]
[a-z-[qz]]
\1
\B
\D
\G
\H
\K
\S
\V
\W
\b
\d
\e
\h
\p{L}, \P{L}
\s
\t
\v
\w
freeformatter.com
java.util.regex.Matcher
lookingAt()
match
matches()
preg_match
regex.larsolavtorvik.com
regexp
search
{0,n}
{n,m}
{n,}
{n}

Examples of regex that can cause regex engine to fail

  • Debuggex (Also has a repository of useful regexes) javascript, python, pcre
  • Recursion (php and perl): (?R), (?0) and (?1), (?-1), (?&groupname)
  • Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems. (blog post written by Stack Overflow's founder)*
  • The only java.lang.String functions that accept regular expressions: matches(s), replaceAll(s,s), replaceFirst(s,s), split(s), split(s,i)
  • find()): A match may be anywhere in the input string (substrings)

@Wildcard - This page is/should definitely be for comment linking after some introductory, general info. But, I've seen it used inappropriately as a direct duplicate too many times.

@sln A rare example of when you should shoot the messenger.

@sln, I think the correct usage would be to look up the answer to a newly asked regex question in this reference, find the linked Q&A that really does answer the new question and is a dupe, mark the new question as a dupe of that post, and add a comment linking to this page.

I don't understand this treatise. While it is (and has) a functional value and good links, nobody that is a beginner will ever understand anything past the first line. Therefore it is useless as an instructional tool. It's title Reference - What does this regex mean? does not tell you what any particular regex means. It is a mish-mash of links.. an overwhelming blend if you will, of the universe of regex constructs from different engines. To make things worse, some people mark regex questions as a direct duplicate of this question. It's sad ..

Note
Rectangle 27 0

Reference What does this regex mean?


$1
(*BSR_ANYCRLF)
(*F)
(*FAIL)
(*PRUNE)
(*SKIP)
(...)
(?!...)
(?:)
(?<!...)
(?<=...)
(?<groupname>regex)
(?=...)
(?>)
(?P<group_name>regexp)
(?P<groupname>regex)
(?|)
*+
*?
++
+?
Matcher
[...]
[.]
[[:alpha:]]
[\w&&[^\d]]
[\w-[\d]]
[^...]
[^2[^0-9]]
[^[^0-9]2]
[^\\D2]
[^]
[a-z-[qz]]
\1
\B
\D
\G
\H
\K
\S
\V
\W
\b
\d
\e
\h
\p{L}, \P{L}
\s
\t
\v
\w
freeformatter.com
java.util.regex.Matcher
lookingAt()
match
matches()
preg_match
regex.larsolavtorvik.com
regexp
search
{0,n}
{n,m}
{n,}
{n}

Examples of regex that can cause regex engine to fail

  • Debuggex (Also has a repository of useful regexes) javascript, python, pcre
  • Recursion (php and perl): (?R), (?0) and (?1), (?-1), (?&groupname)
  • Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems. (blog post written by Stack Overflow's founder)*
  • The only java.lang.String functions that accept regular expressions: matches(s), replaceAll(s,s), replaceFirst(s,s), split(s), split(s,i)
  • find()): A match may be anywhere in the input string (substrings)

@Wildcard - This page is/should definitely be for comment linking after some introductory, general info. But, I've seen it used inappropriately as a direct duplicate too many times.

@sln A rare example of when you should shoot the messenger.

@sln, I think the correct usage would be to look up the answer to a newly asked regex question in this reference, find the linked Q&A that really does answer the new question and is a dupe, mark the new question as a dupe of that post, and add a comment linking to this page.

I don't understand this treatise. While it is (and has) a functional value and good links, nobody that is a beginner will ever understand anything past the first line. Therefore it is useless as an instructional tool. It's title Reference - What does this regex mean? does not tell you what any particular regex means. It is a mish-mash of links.. an overwhelming blend if you will, of the universe of regex constructs from different engines. To make things worse, some people mark regex questions as a direct duplicate of this question. It's sad ..

Note
Rectangle 27 0

Reference What does this regex mean?


$1
(*BSR_ANYCRLF)
(*F)
(*FAIL)
(*PRUNE)
(*SKIP)
(...)
(?!...)
(?:)
(?<!...)
(?<=...)
(?<groupname>regex)
(?=...)
(?>)
(?P<group_name>regexp)
(?P<groupname>regex)
(?|)
*+
*?
++
+?
Matcher
[...]
[.]
[[:alpha:]]
[\w&&[^\d]]
[\w-[\d]]
[^...]
[^2[^0-9]]
[^[^0-9]2]
[^\\D2]
[^]
[a-z-[qz]]
\1
\B
\D
\G
\H
\K
\S
\V
\W
\b
\d
\e
\h
\p{L}, \P{L}
\s
\t
\v
\w
freeformatter.com
java.util.regex.Matcher
lookingAt()
match
matches()
preg_match
regex.larsolavtorvik.com
regexp
search
{0,n}
{n,m}
{n,}
{n}

Examples of regex that can cause regex engine to fail

  • Debuggex (Also has a repository of useful regexes) javascript, python, pcre
  • Recursion (php and perl): (?R), (?0) and (?1), (?-1), (?&groupname)
  • Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems. (blog post written by Stack Overflow's founder)*
  • The only java.lang.String functions that accept regular expressions: matches(s), replaceAll(s,s), replaceFirst(s,s), split(s), split(s,i)
  • find()): A match may be anywhere in the input string (substrings)

@Wildcard - This page is/should definitely be for comment linking after some introductory, general info. But, I've seen it used inappropriately as a direct duplicate too many times.

@sln A rare example of when you should shoot the messenger.

@sln, I think the correct usage would be to look up the answer to a newly asked regex question in this reference, find the linked Q&A that really does answer the new question and is a dupe, mark the new question as a dupe of that post, and add a comment linking to this page.

I don't understand this treatise. While it is (and has) a functional value and good links, nobody that is a beginner will ever understand anything past the first line. Therefore it is useless as an instructional tool. It's title Reference - What does this regex mean? does not tell you what any particular regex means. It is a mish-mash of links.. an overwhelming blend if you will, of the universe of regex constructs from different engines. To make things worse, some people mark regex questions as a direct duplicate of this question. It's sad ..

Note
Rectangle 27 0

Reference What does this regex mean?


$1
(*BSR_ANYCRLF)
(*F)
(*FAIL)
(*PRUNE)
(*SKIP)
(...)
(?!...)
(?:)
(?<!...)
(?<=...)
(?<groupname>regex)
(?=...)
(?>)
(?P<group_name>regexp)
(?P<groupname>regex)
(?|)
*+
*?
++
+?
Matcher
[...]
[.]
[[:alpha:]]
[\w&&[^\d]]
[\w-[\d]]
[^...]
[^2[^0-9]]
[^[^0-9]2]
[^\\D2]
[^]
[a-z-[qz]]
\1
\B
\D
\G
\H
\K
\S
\V
\W
\b
\d
\e
\h
\p{L}, \P{L}
\s
\t
\v
\w
freeformatter.com
java.util.regex.Matcher
lookingAt()
match
matches()
preg_match
regex.larsolavtorvik.com
regexp
search
{0,n}
{n,m}
{n,}
{n}

Examples of regex that can cause regex engine to fail

  • Debuggex (Also has a repository of useful regexes) javascript, python, pcre
  • Recursion (php and perl): (?R), (?0) and (?1), (?-1), (?&groupname)
  • Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems. (blog post written by Stack Overflow's founder)*
  • The only java.lang.String functions that accept regular expressions: matches(s), replaceAll(s,s), replaceFirst(s,s), split(s), split(s,i)
  • find()): A match may be anywhere in the input string (substrings)

@Wildcard - This page is/should definitely be for comment linking after some introductory, general info. But, I've seen it used inappropriately as a direct duplicate too many times.

@sln A rare example of when you should shoot the messenger.

@sln, I think the correct usage would be to look up the answer to a newly asked regex question in this reference, find the linked Q&A that really does answer the new question and is a dupe, mark the new question as a dupe of that post, and add a comment linking to this page.

I don't understand this treatise. While it is (and has) a functional value and good links, nobody that is a beginner will ever understand anything past the first line. Therefore it is useless as an instructional tool. It's title Reference - What does this regex mean? does not tell you what any particular regex means. It is a mish-mash of links.. an overwhelming blend if you will, of the universe of regex constructs from different engines. To make things worse, some people mark regex questions as a direct duplicate of this question. It's sad ..

Note
Rectangle 27 0

Reference What does this regex mean?


$1
(*BSR_ANYCRLF)
(*F)
(*FAIL)
(*PRUNE)
(*SKIP)
(...)
(?!...)
(?:)
(?<!...)
(?<=...)
(?<groupname>regex)
(?=...)
(?>)
(?P<group_name>regexp)
(?P<groupname>regex)
(?|)
*+
*?
++
+?
Matcher
[...]
[.]
[[:alpha:]]
[\w&&[^\d]]
[\w-[\d]]
[^...]
[^2[^0-9]]
[^[^0-9]2]
[^\\D2]
[^]
[a-z-[qz]]
\1
\B
\D
\G
\H
\K
\S
\V
\W
\b
\d
\e
\h
\p{L}, \P{L}
\s
\t
\v
\w
freeformatter.com
java.util.regex.Matcher
lookingAt()
match
matches()
preg_match
regex.larsolavtorvik.com
regexp
search
{0,n}
{n,m}
{n,}
{n}

Examples of regex that can cause regex engine to fail

  • Debuggex (Also has a repository of useful regexes) javascript, python, pcre
  • Recursion (php and perl): (?R), (?0) and (?1), (?-1), (?&groupname)
  • Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems. (blog post written by Stack Overflow's founder)*
  • The only java.lang.String functions that accept regular expressions: matches(s), replaceAll(s,s), replaceFirst(s,s), split(s), split(s,i)
  • find()): A match may be anywhere in the input string (substrings)

@Wildcard - This page is/should definitely be for comment linking after some introductory, general info. But, I've seen it used inappropriately as a direct duplicate too many times.

@sln A rare example of when you should shoot the messenger.

@sln, I think the correct usage would be to look up the answer to a newly asked regex question in this reference, find the linked Q&A that really does answer the new question and is a dupe, mark the new question as a dupe of that post, and add a comment linking to this page.

I don't understand this treatise. While it is (and has) a functional value and good links, nobody that is a beginner will ever understand anything past the first line. Therefore it is useless as an instructional tool. It's title Reference - What does this regex mean? does not tell you what any particular regex means. It is a mish-mash of links.. an overwhelming blend if you will, of the universe of regex constructs from different engines. To make things worse, some people mark regex questions as a direct duplicate of this question. It's sad ..

Note
Rectangle 27 0

Reference What does this regex mean?


$1
(*BSR_ANYCRLF)
(*F)
(*FAIL)
(*PRUNE)
(*SKIP)
(...)
(?!...)
(?:)
(?<!...)
(?<=...)
(?<groupname>regex)
(?=...)
(?>)
(?P<group_name>regexp)
(?P<groupname>regex)
(?|)
*+
*?
++
+?
Matcher
[...]
[.]
[[:alpha:]]
[\w&&[^\d]]
[\w-[\d]]
[^...]
[^2[^0-9]]
[^[^0-9]2]
[^\\D2]
[^]
[a-z-[qz]]
\1
\B
\D
\G
\H
\K
\S
\V
\W
\b
\d
\e
\h
\p{L}, \P{L}
\s
\t
\v
\w
freeformatter.com
java.util.regex.Matcher
lookingAt()
match
matches()
preg_match
regex.larsolavtorvik.com
regexp
search
{0,n}
{n,m}
{n,}
{n}

Examples of regex that can cause regex engine to fail

  • Debuggex (Also has a repository of useful regexes) javascript, python, pcre
  • Recursion (php and perl): (?R), (?0) and (?1), (?-1), (?&groupname)
  • Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems. (blog post written by Stack Overflow's founder)*
  • The only java.lang.String functions that accept regular expressions: matches(s), replaceAll(s,s), replaceFirst(s,s), split(s), split(s,i)
  • find()): A match may be anywhere in the input string (substrings)

@Wildcard - This page is/should definitely be for comment linking after some introductory, general info. But, I've seen it used inappropriately as a direct duplicate too many times.

@sln A rare example of when you should shoot the messenger.

@sln, I think the correct usage would be to look up the answer to a newly asked regex question in this reference, find the linked Q&A that really does answer the new question and is a dupe, mark the new question as a dupe of that post, and add a comment linking to this page.

I don't understand this treatise. While it is (and has) a functional value and good links, nobody that is a beginner will ever understand anything past the first line. Therefore it is useless as an instructional tool. It's title Reference - What does this regex mean? does not tell you what any particular regex means. It is a mish-mash of links.. an overwhelming blend if you will, of the universe of regex constructs from different engines. To make things worse, some people mark regex questions as a direct duplicate of this question. It's sad ..

Note
Rectangle 27 0

Reference What does this regex mean?


$1
(*BSR_ANYCRLF)
(*F)
(*FAIL)
(*PRUNE)
(*SKIP)
(...)
(?!...)
(?:)
(?<!...)
(?<=...)
(?<groupname>regex)
(?=...)
(?>)
(?P<group_name>regexp)
(?P<groupname>regex)
(?|)
*+
*?
++
+?
Matcher
[...]
[.]
[[:alpha:]]
[\w&&[^\d]]
[\w-[\d]]
[^...]
[^2[^0-9]]
[^[^0-9]2]
[^\\D2]
[^]
[a-z-[qz]]
\1
\B
\D
\G
\H
\K
\S
\V
\W
\b
\d
\e
\h
\p{L}, \P{L}
\s
\t
\v
\w
freeformatter.com
java.util.regex.Matcher
lookingAt()
match
matches()
preg_match
regex.larsolavtorvik.com
regexp
search
{0,n}
{n,m}
{n,}
{n}

Examples of regex that can cause regex engine to fail

  • Debuggex (Also has a repository of useful regexes) javascript, python, pcre
  • Recursion (php and perl): (?R), (?0) and (?1), (?-1), (?&groupname)
  • Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems. (blog post written by Stack Overflow's founder)*
  • The only java.lang.String functions that accept regular expressions: matches(s), replaceAll(s,s), replaceFirst(s,s), split(s), split(s,i)
  • find()): A match may be anywhere in the input string (substrings)

@Wildcard - This page is/should definitely be for comment linking after some introductory, general info. But, I've seen it used inappropriately as a direct duplicate too many times.

@sln A rare example of when you should shoot the messenger.

@sln, I think the correct usage would be to look up the answer to a newly asked regex question in this reference, find the linked Q&A that really does answer the new question and is a dupe, mark the new question as a dupe of that post, and add a comment linking to this page.

I don't understand this treatise. While it is (and has) a functional value and good links, nobody that is a beginner will ever understand anything past the first line. Therefore it is useless as an instructional tool. It's title Reference - What does this regex mean? does not tell you what any particular regex means. It is a mish-mash of links.. an overwhelming blend if you will, of the universe of regex constructs from different engines. To make things worse, some people mark regex questions as a direct duplicate of this question. It's sad ..

Note