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 <title>ECMAScript3中数组方法</title>
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//字符串和数组之间相转换的方法 1.join() split()
 /*var str = 'abcdefg';
 console.log(str.split(''));//["a", "b", "c", "d", "e", "f", "g"]
 var arr = [1,2,3,4,5,[6,7,[8,9]]];
 console.log(typeof(arr.join()));//string
 console.log(arr.join());//1,2,3,4,5,6,7,8,9*/
//跟顺序有关的两个方法 2.reverse() sort()
 /*var a = [1,2,4];
 console.log(a.reverse().join());//4,2,1
 var ar = ['arr','brr','evv','cww'];
 console.log(ar.sort());//["arr", "brr", "cww", "evv"]
 var anum = [33,4,3,1,6,99];
 console.log(anum.sort(function(a,b){
 return a-b;
 }))//[1, 3, 4, 6, 33, 99]
 console.log(anum.sort(function(a,b){
 return b-a;
 }))//[99, 33, 6, 4, 3, 1]
 var aN = ['Body','ss','ass'];
 console.log(aN.sort(function(a,b){
 var s = a.toLowerCase();
 var t = b.toLowerCase();
 if(s>t) return -1;//返回的值小于0,则参数应该在前
 if(s<t) return 1;//返回的值大于0,则参数应该在后
 return 0;//等于0,说明顺序无关紧要
 }))//["ss", "Body", "ass"]*/
// 3.截取或添加数组元素返回新数组的方法,特别注意splice()这个方法会修改调用的数组。concat() slice() splice()
 /*var arr = [1,3,4];
 console.log(arr.concat(3,[4,5]));//[1, 3, 4, 3, 4, 5]
 console.log(arr.concat(3,[4,['a','b']]));//[1, 3, 4, 3, 4, ['a','b']]
 var arr1 = 'bnemohioue';
 console.log(arr1.slice(1,4));//nem slice()第一个参数表示开始位置,第二个参数表示结束位置,但不包含第二个函数
 console.log(arr1.slice(2));//emohioue 只有一个参数时代表从开始位置到数组结尾的所有元素。
 console.log(arr1.slice(3,-1))//mohiou 如果出现负数,它表示相对于数组中最后一个元素的位置。参数-1指定了最后一个元素的位置
 var arr2 = [1,2,3,4,5,6,7,8];
 console.log(arr2.splice(3));//[4, 5, 6, 7, 8]
 console.log(arr2);//[1, 2, 3]
 console.log(arr2.splice(2,0,[1,2]));//[]
 console.log(arr2)//[1, 2, [1,2], 3]
 console.log(arr2.splice(2,2,'a','b','c'))//[[1,2], 3]
 console.log(arr2)//[1, 2, "a", "b", "c"]*/
// 4.向数组中尾部或头部添加、删除元素的方法,返回数组新的长度/删除的元素 push()和pop() unshift()和shift()
 /*var arr3 = [2,4,'d'];
 console.log(arr3.push('d','f'));//5
 console.log(arr3);//[2, 4, "d", "d", "f"]
 console.log(arr3.pop());//f
 console.log(arr3);//[2, 4, "d", "d"]
 console.log(arr3.pop());//d
 console.log(arr3);//[2, 4, "d"]
 console.log(arr3.unshift('k','lk'));//5
 console.log(arr3);//["k", "lk", 2, 4, "d"]
 console.log(arr3.shift());//k
 console.log(arr3);//["lk", 2, 4, "d"]*/
// 5.toString()、toLocaleString()是toString()方法的本地方版本。
 console.log([2,3,'f'].toString());//2,3,f 这里不使用任何参数调用join()方法返回的字符串是一样的。将其每个元素转成字符串
 console.log(['s','c','s'].toLocaleString());//s,c,s
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转载于:https://www.cnblogs.com/studyh5/p/9309909.html