ruby regular expression

Regular expressions are a special sequence of characters that can help match or find other strings or string sets, using patterns that maintain a specialized syntax. The regular expression literal is a pattern between a slash or any delimiter%r as follows:Grammar: Copy Code code as follows: /pattern/ /PATTERN/IM # option can be specified %r!/

Most of Ruby's built-in types are similar to other programming languages. Mainly have strings,integers,floats,arrays and so on. However, only the scripting language, such as Ruby,perl, and awk provide support for built-in expression types. Shame: Regular expressions are a powerful text-processing tool, albeit covert. They are very different than simply adding a

Perl, Ruby also uses forward slashes (instead of double quotation marks) to enclose them. if you have never used regular expressions before, maybe they seem to be nothing except Rules (regular), but it is wise to spend a little time learning about them. when you need to perform pattern matching, search, or other operations on strings, its efficient

Speaking of Ruby, of course, we need to mention its regular expression mechanism. As a powerful matching language, regular expressions are increasingly used in different fields, from string verification, matching, to web page extraction. Although some people criticize the matching efficiency with

Regular Expression Regular Expressions are applicable in many scenarios. For example, verify whether the string matches the format, find the matched string, and replace the matched string. Many programming languages support regular expressions with similar syntax. A regular

In the PP file for writing puppet, many of the regular expressions for Ruby are used and are commonly used as follows: Regular expression: [Codesyntax lang= "Ruby"] {}: The number of repetitions (such as {4} indicates that the preceding repeat occurs exactly 4 time

Tutorial on the basic usage of Regular Expressions in Ruby programs, ruby Regular Expressions Most of Ruby's built-in types are similar to other programming languages. Mainly include strings, integers, floats, and arrays. However, only script languages such as Ruby, Perl, an

Detailed description of matching and replacement operations on strings by regular expressions in Ruby, and ruby Regular Expressions Regular Expression matching Speaking of Ruby, of cour

Basic instructions for using regular expressions in Ruby, ruby Regular Expressions Built-in support for regular expressions is usually limited to scripting languages such as Ruby, Perl, and awk. This is a shame: although

This section describes the regular expressions and Ruby Regular Expressions in ruby. A regular expression is a character of a special sequence. It matches or searches for other strings or string sets by using a pattern with specia

An example is provided to explain the regular expressions in Ruby and the regular expressions in ruby. A regular expression is a special character sequence that can help match or find other strings or strings. The pattern used mai

finite automatonDeterministic Finite Automaton DFA engines do not require backtracking (and therefore they never test the same character twice), So matchFast! The DFA engine can also match the longest possible string. However, the DFA engine only contains a limited number of States, so it cannot match a pattern with a reverse reference.Subexpressions cannot be captured.. Representativeness:Awk, egrep, flex, lex, MySQL, Procmail NFA Non-deterministic finite automatic Non-determin

DFA engine they do not require backtracking (and therefore they never test the same characters two times), so the match is fast ! The DFA engine can also match the longest possible string. However, the DFA engine contains only a limited state, so it cannot match a pattern with a reverse reference, and no subexpression can be captured . Representative: awk,egrep,flex,lex,mysql,procmail NFA non-deterministic Finite automaton is a finite automaton, and is divided into tra

$string='April15,2003';$pattern='/(\w+)(\d+),(\d+)/i';$replacement='${1},${3}';echo preg_replace($pattern,$replacement,$string);?> The result of this expression is april1,2003Cause: (\w+) can match April15 completely, but because (\d+) is behind (\w+), in order to be able to match defined rules, (\w+) matches April1, (\d+) matches 5You can change the expression to avoid this situation such as:$pattern = '/

Regular expression is regular expression, it seems that English is better than Chinese understand more, is to check expression characters Not meet the rules!! Regular expressions have a very powerful and very complex object regexp