strings and Arrays in JavaScript

The operation string and operation array in JS are similar.

Take the following array as an example:

var arr = ['e'c'r ' ' o ' ]; var arrnum = [64];

1, determine whether the array

if (arr instanceof Array) {    Console.log (true);} if // ECMAScript 5    Console.log (true);}

2. Format as a string

Console.log (Arr.join (','));

3. Add Delete

Arr.push (' x '//////["C", "R", "O"] arr.unshift (' d '//["D", "C", "R", "O"]

4. Sorting method

Console.log (Arr.reverse ());//["O", "R", "C", "D"]Console.log (Arr.sort ());//["C", "D", "O", "R"]Console.log (Arrnum.sort ());//Convert to String after comparison [4, 6, +]Console.log (Arrnum.sort (Compare));//[4, 6, up, up]Console.log (Arrnum.sort (Compareex));//[4, 6, up, up]functionCompare (A, b) {if(A <b) {return-1; } Else if(A >b) {return1; } Else {        return0; }}functionCompareex (A, b) {returnAb;}

5. Operation method

var arrnew = Arr.concat (' Red ', [' ss ', ' Z '//

Console.log (Arr.slice (2));      // ["R", "O"]console.log (Arr.slice (1, 3));   // ["C", "R"]

//Splice The most powerful return value for the deleted composition of the array itself changesConsole.log (Arr.splice (1, 3));//["C", "R", "O"]Console.log (arr);//["E"]vararr = [' E ', ' C ', ' R ', ' O ']; Console.log (Arr.splice (2, 0, ' add ', ' DD '));//[]Console.log (arr);//["E", "C", "Add", "DD", "R", "O"]vararr = [' E ', ' C ', ' R ', ' O '];console.log (Arr.splice (2, 2, ' Ed ', ' fr '));//["R", "O"]Console.log (arr);//["E", "C", "Ed", "Fr"]

6. Position Method ECMAScript 5

var arr = [' E ', ' C ', ' R ', ' O '];console.log (arr.indexof (//-1//1 // 1

7. Iterative Method ECMAScript 5

varnum = [1, 3, 5, 10, 56, 11];varR = Num.every (function(item, index, array) {//all satisfies return true    return(item% 2 = = 0);}); Console.log (R); R= Num.filter (function(item, index, array) {//Filter    return(item% 2 = = 0);}); Console.log (R); R= Num.some (function(item, index, array) {//returns True if one matches    return(item% 2 = = 0);}); Console.log (R); R= Num.map (function(item, index, array) {//returns the new array    return(item-1);}); Console.log (r);//for each actionNum.foreach (function(item, index, array) {Console.log (item);});

8, reduce the method ECMAScript 5

//parameters: Previous item, current item, ordinal, arrayvarnum = [1, 3, 5, 10, 56, 11];varsum = Num.reduce (function(pre, cur, index, array) {returnPre +cur;});  Console.log (sum); // thevarsum = Num.reduceright (function(pre, cur, index, array) {Console.log (pre+ ' +cur); returnPre-cur;}); Console.log (sum); //-64

9. String

var name = ' Zjzhome '; Console.log (Name.charat (1));  // J Console.log (name.substring (/// and slice like preferred slice//jz//Home // Jzh

String and array in JavaScript