數(shù)組的方法有許多，但來(lái)來(lái)回回常用的也就那幾種，特此記錄，以備遺忘之需。

將數(shù)組合并成字符串

1. toString()
   直接把數(shù)組里的內(nèi)容變成一個(gè)字符串
   var arr = [12,25,30,92]; var arr1 = arr.toString(); //arr1 = 12,25,30,92
2. join()
   以某種符號(hào)將數(shù)組內(nèi)容串聯(lián)成一個(gè)字符串
   var arr = [12,25,30,92]; var arr1 = arr.join('*'); //arr1 = 12*25*30*92

增加數(shù)組內(nèi)容

1.push()
添加的內(nèi)容按順序放在數(shù)組最后面，并自動(dòng)加長(zhǎng)度

var arr = [12,25,30,92];
var arr1 = arr.push(51，65); //arr1 = [12,25,30,92,51,65]

2.unshift()
添加的內(nèi)容按順序放在數(shù)組的最前面，并自動(dòng)增加長(zhǎng)度

var arr = [12,25,30,92];
var arr1 = arr.unshift(51，65); //arr1 = [51,65,12,25,30,92]

取出數(shù)組內(nèi)容

1.pop()
取出數(shù)組最后一個(gè)元素，并返回該值且在數(shù)組中消失

var arr = [12,25,30,92];
var poped = arr.pop();
 //arr = [12,25,30]   poped = 92

2.shift()
取出數(shù)組第一個(gè)元素，并返回該值且在數(shù)組中消失

var arr = [12,25,30,92];
var shifted = arr.shift();
 //arr = [25,30,92]   shifted = 12

3.slice(begin,end)
淺復(fù)制了數(shù)組內(nèi)容,begin為開(kāi)始復(fù)制的位置，end為結(jié)束復(fù)制的位置

var arr = [12,25,30,92];
var arr1 = arr.slice(1,3);
 //arr1 = [25,30,92]  

排序

排序的方法倒是只有一種，即sort（），但是分為升序和降序
1.升序
默認(rèn)為升序

var arr = [12,0,25,30,92];
var arr1 = arr.sort();
//arr1 = [0,12,25,30,92]

還有另一種寫(xiě)法記得ab不能寫(xiě)反

var arr = [12,0,25,30,92];
var arr1 = arr.sort(functiion(a,b){
      return a-b;
});
//arr1 = [0,12,25,30,92]

2.降序

var arr = [12,0,25,30,92];
var arr1 = arr.sort(functiion(a,b){
      return b-a;
});
//arr1 = [92,30,25,12,0]

替換數(shù)組內(nèi)容

splice(start,items,inplace);此方法從數(shù)組的start位置開(kāi)始刪除items個(gè)元素，并添加inplace元素

var myFish = ['angel', 'clown', 'mandarin', 'surgeon'];
// removes 0 elements from index 2, and inserts 'drum'
var removed = myFish.splice(2, 0, 'drum');
    // myFish is ['angel', 'clown', 'drum', 'mandarin', 'surgeon']
    // removed is [], no elements removed
// myFish is ['angel', 'clown', 'drum', 'mandarin', 'surgeon']
 // removes 1 element from index 3
removed = myFish.splice(3, 1);
    // myFish is ['angel', 'clown', 'drum', 'surgeon']
    // removed is ['mandarin']
// removes 1 element from index 2, and inserts 'trumpet'
removed = myFish.splice(2, 1, 'trumpet');
    // myFish is ['angel', 'clown', 'trumpet', 'surgeon']
    // removed is ['drum']
 // removes 2 elements from index 0, and inserts 'parrot', 'anemone' and 'blue'
removed = myFish.splice(0, 2, 'parrot', 'anemone', 'blue');
    // myFish is ['parrot', 'anemone', 'blue', 'trumpet', 'surgeon']
    // removed is ['angel', 'clown']
 // removes 2 elements from index 2
removed = myFish.splice(myFish.length -3, 2);
    // myFish is ['parrot', 'anemone', 'surgeon']
    // removed is ['blue', 'trumpet']

這一個(gè)引用了devdocs的demo

合并數(shù)組

concat();將兩個(gè)數(shù)組合并成一個(gè)新數(shù)組，并返回該數(shù)組

var arr1 = [12,23,34];
var arr2 = ['hello','world'];
var arr3 =arr1.concat(arr2);
//arr3 = [12,23,34,'hello','world']

哪個(gè)數(shù)組使用了此方法，哪個(gè)就在前