10th-Regular Expressions

10.1 Regular Expressions

　　10.1.1 Direct Volume characters

<script type= "Text/javascript" >    var pattern =/s$/;    Console.log (Object.prototype.toString.call (pattern));    Console.log (typeof  pattern);     // ^$.*+?=!:| \ \ () []{}</script>

View Code

　　10.1.2 Character class

<script type= "Text/javascript" >//The character class (character Class) is formed by placing the direct volume character in square brackets, and a character class can match any character it contains    //any character in square brackets [...]    //[^ ...] any character not in square brackets    //. Any character except newline characters and other Unicode line terminators    //\w A word that consists of any ASCII character, equivalent to [a-za-z0-9]    //\w Any word that is not an ASCII character, equivalent to [^a-za-z0-9]    //\s Any Unicode whitespace character    //\s any non-Unicode whitespace characters, note that \w and \s are different    //\d any ASCII number, equivalent to [0-9]    //\d any character except ASCII digits, equivalent to [^0-9]    //[\b] push lattice direct volume</script>

View Code

　　10.1.3 Repeat

<script type= "Text/javascript" >    //{n,m} matches the previous item at least n times, but not more than M    //{n,}  match previous N or more times    // {n} matches the previous item n times    //? Match the previous item 0 or 1 times, which means the previous item is optional, equivalent to {0,1}    //+ Matches the previous item 1 or more times, equivalent to {1,}    //* matches the previous item 0 or more times, equivalent to {0,}    /\d{2,4}/    /\w{3}\d?/    /\s+java\s+/    /[^ (]*/</script>

View Code

　　10.1.4 selection, grouping and referencing

<script type= "Text/javascript" >    // Regular expression syntax also contains the specified selection, sub-expression grouping, and referring to the special characters of the previous sub-expression    //  | Select to match the subexpression to the left of the symbol or to the right sub-expression    //(...) combination, combining several items into a single unit, which is available through "*", "+", "?" and "|" Such symbols are modified    // and the strings that match this combination can be remembered for subsequent references using    //(?...) only combinations, Combine items into a single cell, but do not remember matching characters in the group    //\ n and nth grouping the first matching characters, the group is a subexpression in parentheses (also possibly nested), the group index is left-to-right, the number of left parenthesis, " (?: "Form of grouping does not encode </script>

View Code

　　10.1.5 Specifying a matching location

<script type= "Text/javascript" >    //^ matches the beginning of the string, in a multiline search, matches the beginning of the line    //$ Matches the end of the string, in a multiline search, the end of the match line    //\b matches the boundary of a word, in short, the position between the character \w and \w, or the position between the character \w and the beginning or end of the string    //\b matches the position    of a non-word boundary // (? =p) 0 wide forward predicate assertion, to go to the next character all matches p, but cannot include those characters    that match p // (?! P) 0 Wide negative forward assertion, requires the next character not P-match </script>

View Code

　　10.1.6 modifier

<script type= "Text/javascript" >    //I performs a case-insensitive match    //G performs a global match, in short, That is to find all matches, instead of stopping    //m Multi-line matching pattern after finding the first one, ^ matches the beginning of a line and the beginning of the string, the end of the matching line and the end of the string </script>

View Code

10.2 String method for pattern matching

<script type= "Text/javascript" >    console.log ("JavaScript". Search (/script/i));    // returns the starting position of the first substring to match, and returns 1    if no matching substring is found // var text;    // Text.replace (/javascript/gi, "JavaScript");    // var quote =/"([^"]*) "/g;    // text.replace (Quote, ' "$");    // Match    // Splite</script>

View Code

10.3 RegExp Object

　　10.3.1 Properties of RegExp

<script type= "Text/javascript" >    / / Each RegExp object contains 5 properties    //source    A read-only string that contains the literal    //Global    Read-only Boolean value of the regular expression to indicate whether the regular expression has a modifier g    //  IgnoreCase    Read-only Boolean value that indicates whether the regular expression has a modifier i    //Multiline Read-only Boolean value that indicates whether the regular expression has a modifier m    ///LastIndex This property is stored at the beginning of the next retrieval of the entire string </script>

View Code

　　Methods of 10.3.2 RegExp

<script type= "Text/javascript" >    //regexp.exec ()    //regexp.test ()     //regexp.search ();    // regexp.replace ()    // Regexp.match (); </script>

View Code

10th-Regular Expressions