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Regular expression

A regular expression (shortened as regex or regexp), sometimes referred to as a rational expression, is a sequence of characters that specifies a match pattern in text. Usually such patterns are used by string-searching algorithms for "find" or "find and replace" operations on strings, or for input validation.

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Overview

History

Patterns

Basic concepts

Formal language theory

Syntax

Patterns for non-regular languages

Implementations and running times

Unicode

Language support

Uses

Examples

Induction

Advanced semantic analysis

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Map overview Semantic statistics

Regular expression

Nodes199
Edges198
Triples176
Avg. degree1.99
Density0.01005
Components1

How this topic connects Entity context

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Regular expression

Top relations

related to Unicode · 52
Regular expression → Alphabetic, Armenian, As ASCII, ASCII, ASCII-based, Basic Latin, Basic Multilingual Plane, Binary, Block, Case, Chinese, Cousins, Currently, Dash, Devanagari, Exactly, Examples, Extending ASCII-oriented, For, GC
related to history · 25
Regular expression → Among, Around, Compatible Time-Sharing System, Douglas, For, Global, He, IBM, JIT, Ken Thompson, Kleene, Kleene's, McCulloch, Other, Pitts's, Print, QED, Regular, Ross, SNOBOL
related to IEEE POSIX Standard · 14
Regular expression → Although POSIX, Basic Regular Expressions, BRE, ERE, Extended Regular Expressions, For, Furthermore, GNUgrephas, Perl, POSIX, Simple Regular Expressions, SRE, The, The IEEE POSIX
related to Expressive power and compactness · 11
Regular expression → However, In, L4, Lk, On, Rc, Regular, Some, Sometimes, The, There
related to External links · 9
Regular expression → Base Specifications, Expressions, IEEE Std, Information, ISO/IEC/IEEE, Issue, Open GroupOpen, Portable Operating System Interface, POSIX
related to Basic concepts · 8
Regular expression → Haen, Haendel, Han, Handel, However, Hän, Händel, Most
related to Patterns · 8
Regular expression → ASCII, Each, For, Pattern, The, Therefore, Together, Wildcard
related to Implementations and running times · 7
Regular expression → Constructing, DFA, NFA, Note, The, The DFA, There
related to Patterns for non-regular languages · 7
Regular expression → For, However, Many, NP-complete, The, This, WikiWiki
related to IETF I-Regexp · 6
Regular expression → An Interoperable Regular Expression, Format, I-Regexp, IETF RFC, It, Thus

Important terminology Word statistics

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Important terminology

regular expressions expression regex posix syntax character string example characters set perl many languages pattern used language matches unicode regexes

Entity relationships Subject–Predicate–Object triples

SubjectPredicateObjectConfidenceSrc
sedinstance ofin text processing utilities0.80text
AWKinstance ofin text processing utilities0.80text
and in lexical analysisinstance ofin text processing utilities0.80text
viinstance ofand in other programs0.80text
and Emacsinstance ofand in other programs0.80text
Boostinstance ofSome languages and tools0.80text
PHP support multiple regex flavorsinstance ofSome languages and tools0.80text
capture groupsinstance ofit lacks advanced features0.80text
lookaheadinstance ofit lacks advanced features0.80text
and backreferencesinstance ofit lacks advanced features0.80text
the reverse scaninstance ofbased algorithms and related DFA optimization techniques0.80text
POSIXinstance ofa fixed property of some regexp languages0.80text

Related concept clusters Concept neighborhoods

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    Min side: 3
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