Search results
Results from the WOW.Com Content Network
prefix:namespace: string filters a namespace down to one or more pages where string matches the pagename's beginning characters. [13] For example, prefix:help:t finds Help pagenames that begin with "T". When the string has zero characters all pages in the given namespace are found.
Regular Expression Flavor Comparison – Detailed comparison of the most popular regular expression flavors; Regexp Syntax Summary; Online Regular Expression Testing – with support for Java, JavaScript, .Net, PHP, Python and Ruby; Implementing Regular Expressions – series of articles by Russ Cox, author of RE2; Regular Expression Engines
Preceding any other character with a backslash is harmless. For example, insource:/yes\.\no/ will search for pages containing the literal string "yes.no" (case-sensitive). Regex experts should note that \n does not mean "newline," \d does not mean "digit," and so on: In MediaWiki syntax, the only use of \ is to escape metacharacters.
Regular expressions (or regex) are a common and very versatile programming technique for manipulating strings. On Wikipedia you can use a limited version of regex called a Lua pattern to select and modify bits of text from a string. The pattern is a piece of code describing what you are looking for in the string.
For example, in the text string: The quick brown fox jumps over the lazy dog. the string is not implicitly segmented on spaces, as a natural language speaker would do. The raw input, the 43 characters, must be explicitly split into the 9 tokens with a given space delimiter (i.e., matching the string " "or regular expression /\s{1}/).
Oniguruma (鬼車) is a free and open-source regular expression library that supports a variety of character encodings, written by K. Kosako.The Ruby programming language, in version 1.9, as well as PHP's multi-byte string module (since PHP5), use Oniguruma as their regular expression engine. [2]
Perl Compatible Regular Expressions (PCRE) is a library written in C, which implements a regular expression engine, inspired by the capabilities of the Perl programming language. Philip Hazel started writing PCRE in summer 1997. [ 3 ]
Regular expressions can often be created ("induced" or "learned") based on a set of example strings. This is known as the induction of regular languages and is part of the general problem of grammar induction in computational learning theory.