A formal syntactic specification widely implemented in the Unix language family for reference to strings. For example, the regular expression denoting a string of alphanumerics (i.e., letters or numbers) is [A-Za-z0-9
An expression defined using operators that specifies what characters to expect in an input unit and in which order. These are used to define certain lexical units that you wish to recognize, such as dates, prices, etc.
(RE) A string of characters specifying a pattern. Usually, wildcards (match to anything) and variable positions (match to one of the following) are allowed.
A useful way of getting a program to match particular bits of text. Often used in scripting languages to process data files.
A text string that uses special characters to represent ranges or classes of characters for the purpose of pattern matching.
A Scripting feature that matches the patterns of characters in a String of text.
A concise and flexible notation for finding and replacing patterns of text. The notation comprises two basic character types: literal (normal) text characters, which indicate text that must exist in the target string, and metacharacters, which indicate the text that can vary in the target string. You can use regular expressions to quickly parse large amounts of text to find specific character patterns; extract, edit, replace, or delete text substrings; or to add the extracted strings to a collection in order to generate a report.
See Regular Expressions.
A compact way of specifying a group of strings that all match some criteria. More.
A string that can describe several sequences of characters.
A pattern of characters used to match against the same characters in a search. They usually include special characters, which represent things other than themselves, to refine the search. Regular expressions empower utilities like grep, sed and awk. Although similar to shell wildcards there are differences so be careful.
A way of expressing a text pattern for matching purposes, more information ...
Is a way of representing data using symbols. They are often used within matching, searching or replacing algorithms.
an expression in a regular language, which is equivalent in power to a finite state automata (FSA), drawn from a particular alphabet. Regular expressions allow listing of alternatives (usually with the vertical bar), concatenation (usually by writing one part of the expression after another), and repetition (usually shown with the asterisk to indicate zero or more occurrences or the plus sign to represent 1 or more). Thus, binary strings can be described by the expression "(0|1)+". Note that UNIX allows regular expressions in many contexts including in editors, command language interpreters, and string search programs.
A Regular Expression is a notation used describe patterns of characters. In programming language theory, they are often used to describe a languages' terminals. For more information, please see the Regular Expression page
A syntax that expresses conditions on strings. The syntax used by the W3C XML Schema for its patterns is very close to the syntax introduced by the Perl programming language. A regular expression is composed of elementary pieces.
A string of characters that selects text.
A sequence of characters that represents a pattern.
A formula for matching strings that follow some pattern. Regular expressions are made up of normal characters and metacharacters. In the simplest case, a regular expression looks like a standard search string. For example, the regular expression "testing" contains no metacharacters. It will match "testing" and "123testing" but it will not match "Testing". Metacharacters match some expressions like '.' metacharacter match any single character in a search string.
A shorthand for expressing patterns of text. An expression which generates a language from the operations union (alternation), concatenation, and concatenation closure.
A regular expression, or "regex", is a way of describing a string of text using metacharacters or wild-card symbols. For example, the statement fly.*so[au]p means "any phrase beginning with 'fly' and ending in 'soup' or 'soap'". If you searched for that expression, you'd find both "fly in my soup" and "fly in my soap." There's not room here to go into depth, but if you want, have a look at the documentation for the grep command by opening a command line and typing in man grep.
A regular expression (RegExp, for short) is a formula for matching strings that follow some pattern. You can think of regular expressions as wildcard characters that enforce a validation pattern. Regular expressions have a special syntax. To learn more about defining a regular expression, visit http://sitescooper.org/tao_regexps.html.
A regular expression, used to search for matching text in a file or network packet, consists of alpha-numeric characters and symbols. A regular expression is used in the Custom Match box of the Rule Properties window when defining a custom rule.
A single consensus expression derived from a conserved region of a sequence alignment, and used as a characteristic signature of family membership. Synonymous terms: rule, pattern.
a powerful theoretical tool which is used to search and match text strings. It lets one specify patterns these strings must obey. Many UNIX utilities use it: sed, awk, grep, perl and others.
A text expression that specifies a pattern of text to be matched (as opposed to matching specific characters).
A regular expression is a pattern that can match various text strings, such as all the words that begin with the letter S, or every 7-digit phone number, or even every sentence with two apostrophes in it and no capital letter T. Regular expressions are often useful for advanced "search and replace" tasks. Thus, it is imperative to properly test the regular expression for any unexpected result. Files should be saved prior to running any regular expression so that you can resort to a saved file if a problem be discovered.
A form of expression that is used in proxy for wildcard patterns for access control.
See `` regexp.''
A notation for matching any sequence of characters. The notation is used to describe the form of a sequence of characters, rather than the characters themselves. Regular expressions consist of literal characters, which match only themselves, and metacharacter
A string of text and special characters used for pattern matching.
A way of specifying and matching strings for shells (filename wildcarding), grep (file searches), sed, and awk.
Regular expressions offer a way to search documents using pattern matching. Such tools let you mix substrings, wildcards, and repetitive sequences to create a complex key to search against, resulting in a powerful and specific set of matches. Regular expressions are not designed for searching by content, but useful for finding certain files or very specific data strings.
a string following the rules of a regular language, used to describe a class of strings (that can be recognized by an FSA), allowing alternatives, specifying a sequence, and indicating number of occurrences (0, 1, any number, at least one)
OracleAS Web Cache supports the POSIX 1003 extended regular expressions for URLs, as supported by Netscape Proxy Server 2.5. See Also:: http://www.cs.utah.edu/dept/old/texinfo/regex/regex_toc.html for regular expression syntax
regular expression as defined in XML Schema Part 2: Datatypes, Appendix F.
(regexp) A regular expression is an expression used for pattern matching. Documentation
An expression syntax used by many operating systems, especially UNIX, to specify similarity between words and phrases. A powerful way to express wildcards in textual expressions.
(Regex) A way of describing a pattern in text - for example, "all the words that begin with the letter A" or "every 10-digit phone number" or even "Every sentence with two commas in it, and no capital letter Q". Regular expressions are useful in Apache because they let you apply certain attributes against collections of files or resources in very flexible ways - for example, all .gif and .jpg files under any "images" directory could be written as "/images/.*(jpg|gif)$". Apache uses Perl Compatible Regular Expressions provided by the PCRE library.
A regular expression is a pattern that can match various text strings; for example, ` l[0-9]+' matches `' followed by one or more digits. See Regexps.
(1.) A set of characters, meta characters, and operators that define a string or group of strings in a search pattern. (2.) A string containing wildcard characters and operations that define a set of one or more possible strings. Contrast with literal string.
(1) A mechanism to select specific strings from a set of character strings. (2) A set of characters, metacharacters, and operators that define a string or group of strings in a search pattern. (3) A string containing wildcard characters and operations that define a set of one or more possible strings. Show related articles
In computing, a regular expression (abbreviated as regexp or regex, with plural forms regexps, regexes, or regexen) is a string that describes or matches a set of strings, according to certain syntax rules. Regular expressions are used by many text editors and utilities to search and manipulate bodies of text based on certain patterns. Many programming languages support regular expressions for string manipulation.