JavaScript Regular Expressions

/*Review Var obj= new number (2), alert (number.min_value), var num = new Number (22E3), alert (num), alert (Isfinite (num));//   Determine if the specified range is exceeded var person={fname: "John", lname: "Doe", Age:25};var txt= ""; for (x in person) {txt=txt + person[x]; } alert (TXT); ------------------------------------------Regular Expressions (regular expression) Creation method: 1. Use the new operator var reg = new RegExp ("box"); alert (reg);//return/box/var reg = new RegExp ("box", "IG");//The optional parameters of the pattern modifier: I-ignore case, G-Global match; M-Multiline match. Alert (reg);//return/box/gi2. create var reg =/box/;alert (reg) using the literal method;//return/box/var reg =/box/ig;alert (reg);//return/ Box/gi---------------------------var pattern = new RegExp ("box"), var str = new String ("box"), Alert (Pattern.test (str))  ;//return Falsevar pattern = new RegExp ("box", "I"); var str = new String ("This is a box"); Alert (Pattern.test (str));//return Truealert (/box/.test ("This is a box!"); /falsealert (/box/i.test ("This is a box!"); /truealert (/box/.exec ("This is a box!"); /return Nullalert (/box/i.exec ("This is a box!"); /return box alert (/bOx/i.exec ("This box is a box!"); /return Boxalert (/box/i.exec ("This box is a box!")); Return Boxalert (/box/ig.exec ("This box is a box!")); /return Boxvar pattern = new RegExp ("box", "I"); var str = new String ("This is a box! That box is a box! "); var result = pattern.exec (str), var result2 = Str.match (pattern), method of//string object alert (typeof result2); alert (result2[0]); var pattern = new RegExp ("box", "IG");//Global match, that is to find all matching items var str = new String ("This box is a box! That box is a box! "); var result = pattern.exec (str);//returns the first matched string alert (result[1]);//return undefined proves that the return is not an array var result2 = Str.match ( pattern);//string Object Method Alert (typeof result2); alert (result2[1]);//return Box proves that the return is an array var pattern = new RegExp ("box", " I "); var str = new String (" This box is a box! That box is a box! "); var result = Str.search (pattern),//string object method Alert (Result),//return 5 returns the first matching position, returns -1var pattern = new RegExp ("box "," I ");//does not turn on global var str = new String (" This box is a box! That box is a box! "); var result = Str.replace (patTern, "Tom"); alert (result);//this Tom is a box! That box is a box!var pattern = new RegExp ("box", "IG");//Turn on global var str = new String ("This box is a box! That box is a box! "); var result = Str.replace (pattern, "Tom"); alert (result);//this Tom is a tom! That's Tom is a tom!var pattern = new RegExp ("!", "IG");//Turn on global var str = new String ("This box is a box! That box is a box! "); var result = Str.split (pattern), alert (result),//this box is a box, which box is a box,var pattern = new RegExp ("!", "IG");// Turn on global var str = new String ("This box is a box! That box is a box! "); var result = Str.split (pattern); for (Var i=0;i<result.length;i++) {alert (result[i]);} var pattern = new RegExp ("!", "IG");//Turn on global var str = new String ("This box is a box! That box is a box! "); var result = Str.split (pattern), for (Rs in result) {alert (RS);//return 0, return 1, return 2}var pattern = new RegExp ("box", "IG");//Turn on global var str = new String ("This box is a box! That box is a box! "); var result = Pattern.test (str);//alert (regexp.input);//this bOx is a box! That box is a Box!alert (regexp.leftcontext), alert (regexp.rightcontext), alert (regexp.lastmatch), var pattern =/g. gle/; . Represents any character other than line break var str = "Google"; alert (Pattern.test (str));//truevar pattern =/go*gle/; o* represents 0 to multiple Ovar str = "Gooogle"; Alert (Pattern.test (str));//truevar pattern =/go+gle/; o+ represents 1 to multiple Ovar str = "Gooogle"; Alert (Pattern.test (str));//truevar pattern =/go?gle/; O? denotes 0, or 1 var str = "Ggle"; Alert (Pattern.test (str));//truevar pattern =/go{2,4}gle/; o{2,4} represents 2 and 4var str = "Google", alert (Pattern.test (str)),//truevar pattern =/go{2}gle/; O{2} indicates that only 2 ovar str = "Google" are present; alert (Pattern.test (str));//truevar pattern =/go{2,}gle/; O{2,} indicates that O appears 2 or more than 2 var str = "Gooogle"; Alert (Pattern.test (str));//truevar pattern =/go[a-z]gle/; [A-z] represents any of the 26 lowercase letters of var str = "Google"; alert (Pattern.test (str));//truevar pattern =/go[0-9]gle/; [0-9] denotes any var str = "Go8gle" in 0~9; alert (Pattern.test (str));//truevar pattern =/go[a-za-z0-9]gle/; [A-za-z0-9] is a compound notation that represents 26Any of the uppercase or lowercase letters or numbers of var str = "Go8gle"; Alert (Pattern.test (str));//truevar pattern =/go[^0-9]gle/; [^0-9] represents any one of the characters in non-0~9 var str = "Go8gle"; Alert (Pattern.test (str));//falsevar pattern =/^go[0-9]gle/; ^ indicates starting from scratch to match var str = "Ggo8gle"; Alert (Pattern.test (str));//falsevar pattern =/go\wgle/; \w denotes any letter, number, or underscore equivalent to [a-za-z0-9_]var str = "Go_gle"; Alert (Pattern.test (str));//truevar pattern =/go\wgle/; \w denotes any non-alphabetic, non-numeric, non-underlined character, equivalent to [^a-za-z0-9_]var str = "Go_gle"; Alert (Pattern.test (str));//falsevar pattern =/go\dgle/ ; \d represents any number, equivalent to [0-9]var str = "Go9gle"; Alert (Pattern.test (str));//truevar pattern =/go\dgle/; \d represents any non-numeric character, equivalent to [^0-9]var str = "Go9gle"; Alert (Pattern.test (str));//falsevar pattern =/google$/; $ indicates starting at end of line to match var str = "Ggoogle"; Alert (Pattern.test (str));//truevar pattern =/goo\sgle/; \s Find white space characters. var str = "Ggoo gle"; Alert (Pattern.test (str));//truevar pattern =/google\b/; \b matches the word boundary. Similar to $var str = "Ggoogle"; Alert (Pattern.test (str));//truevar pattern =/google|baidu|bing/; Vertical Bar | Indicates a match or selectionSelect mode var str = "Ggoogle"; Alert (Pattern.test (str));//truevar pattern =/(google|baidu|bing) s/; Vertical Bar | Indicates matching or selection mode var str = "Ggoogles"; Alert (Pattern.test (str));//truevar pattern =/google{4,8}$/; Indicates the end of E appears 4~8 times var str = "ggoogleeee"; Alert (Pattern.test (str));//truevar pattern =/(Google) {4,8}$/; Brackets denote grouping, indicating that Google appears at the end of 4~8 var str = "Ggooglegooglegooglegoogle"; Alert (Pattern.test (str));//truevar pattern =/8 (. *) 8/; Group var str = "Goo8google8gle";//pattern.test (str);//pattern.exec (str); Str.match (pattern); alert (regexp.$1);// Google regexp.$1 represents the matching string for the first grouping in the get pattern var pattern =/8 (. *) 8/; Group var str = "This is 8google8";d ocument.write (str.replace (Pattern, "<strong>google</strong>")); var Pattern =/8 (. *) 8/; Group var str = "This is 8google8";d ocument.write (str.replace (Pattern, "<strong>$1</strong>")); var pattern = /8 (. *) 8/; Group var str = "This is 8google8";d ocument.write (str.replace (Pattern, "<strong>$1</strong>")); var pattern = /[a-z]/; var str = "You love"; Alert (STR.REplace (Pattern, "1"));//1ou Lovevar pattern =/[a-z]+/; + greedy mode var str = "You love"; Alert (str.replace (Pattern, "1"));//1 Lovevar pattern =/[a-z]+?/; Use +? lazy mode var str = "You love"; Alert (str.replace (Pattern, "1"));//1ou Lovevar pattern =/8 (. *) 8/; Using greedy mode var str = "This is 8google8 8google8 8google8";d ocument.write (str.replace (Pattern, "<strong>$1</ Strong> "));//this is <strong>google8 8google8 8google</strong>var pattern =/8 (. *?) 8/; Using the lazy mode var str = "This is 8google8 8google8 8google8";d ocument.write (str.replace (Pattern, "<strong>$1</ Strong> ")//this is <strong>google</strong> 8google8 8google8 var pattern =/8 (. *?) 8/ G Use lazy mode to turn on global var str = "This is 8google8 8google8 8google8";d ocument.write (str.replace (Pattern, "<strong>$1< /strong> "));//this is <strong>google</strong><strong>google</strong><strong> Google</strong>var pattern =/8 ([^8]*) 8/g; Another kind of inertia that masks 8 matches, turns on global var str = "This is 8GOOGLE8 8google8 8google8 ";d ocument.write (str.replace (Pattern," <strong>$1</strong> "));//this is <strong >google</strong><strong>google</strong><strong>google</strong>var pattern =/8 ([ ^8]*) 8/g; Another inertia, masking 8 matches, turns on global var str = "This is 8google8 8google8 8google8";d ocument.write (str.replace (Pattern, "<strong> $1</strong> "));//this is <strong>google</strong><strong>google</strong><strong >google</strong>var pattern=/(\d+) ([A-z])/;  Capture-type grouping, where all groupings capture returns VAR str= "123abc", var a=pattern.exec (str), alert (a[0]),//123A returns the string matched to alert (a[1]);//123 Returns the string that the first packet matches to alert (a[2]);//a returns the string to which the second packet matches the Var pattern=/(\d+) (?: [A-z])/;  A non-capturing grouping, simply add a: var str= "123abc", var a=pattern.exec (str), alert (a[0]), and//123a return the matched string alert (a[1]);//123 Returns the string that the first packet matches to alert (a[2]);//undefined returns the string Console.log ("Test Zhangweiwen") to which the second grouping matches; var pattern=/(a? B? (c?))) /;//nested matching, from outside to inside var str= "abc"; Alert (Pattern.exec (str));//abc,abc,bc,cvar PattErn=/goo (=gle)/;//must be followed by GLE in order to return to Goovar str= "Google"; alert (Pattern.exec (str));//goovar pattern=/[1-9][0-9]{5}/; var str= "741027";//must be 6 digits, must be a number, first cannot be 0alert (Pattern.test (str)), Alert (Str.match (pattern)), Var pattern=/^\w*\.zip|  7z&/;     Letters, numbers, underscore the name of the compressed file var str= "Study_2015.zip"; Alert (Pattern.test (str)), Var pattern=/(\s+)/g;var str= "Goog le Alert (str.replace (Pattern, ","));//alert ("|"); +pattern.exec (str) + "|"); Alert (Str.match (pattern)), Var pattern=/(\w+)/g;var str= "goog le a"; Alert (str.replace (Pattern, ","));//aler T ("|"  +pattern.exec (str) + "|"); |goog,goog|  The first represents all the groupings returned, and the second GOOG indicates that the first packet returned matches the string alert (Str.match (pattern)); Goog,le,a returns all matches to the string Var pattern=/^\s+ (. +?)   \s+$/; /.+/indicates that the greedy mode/.+?/represents the lazy mode var str= "goog le"; Alert ("|"  +str.replace (Pattern, "$") + "|");  Replace alert (regexp.$1) with the matching result string for the first grouping. You can view the matching results for the first grouping*/

JavaScript Regular Expressions