【小白笔记】js 数组操作

一、concat()：连接两个或更多数组

var arr1 = new Array("1","2","3");

var arr2 = new Array("4","5","6");

console.log(arr1.concat(arr2)); //输出结果：["1", "2", "3", "4", "5", "6"]

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二、pop()：删除并返回数组最后一个元素

var arr = new Array("1","2","3");

console.log(arr.pop()); //输出结果：3

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三、shift()：删除并返回数组第一个元素

var arr = new Array("1","2","3");

console.log(arr.shift()); //输出结果：1

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四、push()：在数组最后添加一个或多个元素

var arr = new Array("1","2","3");

console.log(arr.push("4","5","6")); //输出结果：6

注：返回值为新数组长度

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五、unshift()：在数组开头添加一个或多个元素

var arr = new Array("1","2","3");

console.log(arr.unshift("4","5","6")); //输出结果：6

注：返回值为新数组长度

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六、splice()：删除并添加新元素

splice("添加元素的位置","从添加位置开始删除元素的个数【0为不删除】","要添加的元素【不填时相当于只删除元素】")

var arr = new Array("1","2","3");

console.log(arr.splice(1,1,4)); //输出结果：2

console.log(arr.splice(1,2)); //输出结果：2,3

注：返回值为删除的元素

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七、reverse()：数组按下标倒叙排列

var arr = new Array("1","0","3");

console.log(arr.reverse()); //输出结果：["3", "0", "1"]

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八、sort()：数组元素排序

var arr1 = new Array(1,0,3);

var arr2 = new Array("1","0","3");

var arr3 = new Array("a","c","b");

var arr4 = new Array("Z","z","a");

var arr5 = new Array("Z","a",2);

console.log(arr1.sort()); //输出结果：[0, 1, 3]

console.log(arr2.sort()); //输出结果：["0", "1", "3"]

console.log(arr3.sort()); //输出结果：["a", "b", "c"]

console.log(arr4.sort()); //输出结果：["Z", "a", "z"]

console.log(arr5.sort()); //输出结果：[2, "Z", "a"]

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八、slice()：返回数组中指定元素

slice("起始位置[为负值时反向开始，如-1代表最后一个元素]","结束位置[不填时为从起始位置截取到最后]")

var arr = new Array("1","2","3","4","5","6");

console.log(arr.slice(2,5)); //输出结果：["3", "4", "5"]

注：截取时不包括最后一位

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九、join()：数组转成字符串并用制定字符连接

var arr = new Array("a","b","c");

console.log(arr.join()); //输出结果：a,b,c

console.log(arr.join("+")); //输出结果：a+b+c

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十、toString()：数组转字符串

var arr = new Array("a","b","c");

console.log(arr.toString()); //输出结果：a,b,c

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不常用：

1、valueof()：返回 数组 对象的原始值

2、toSource()：代表对象的源代码

3、toLocalString()：转换为本地数组，并返回结果