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<title>ECMAScript3中數組方法</title>
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//字符串和數組之間相轉換的方法 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*/
//跟順序有關的兩個方法 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，則參數應該在前
if(s<t) return 1;//返回的值大于0，則參數應該在后
return 0;//等于0，說明順序無關緊要
}))//["ss", "Body", "ass"]*/
// 3.截取或添加數組元素返回新數組的方法，特別注意splice()這個方法會修改調用的數組。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()第一個參數表示開始位置，第二個參數表示結束位置，但不包含第二個函數
console.log(arr1.slice(2));//emohioue 只有一個參數時代表從開始位置到數組結尾的所有元素。
console.log(arr1.slice(3,-1))//mohiou 如果出現負數，它表示相對于數組中最后一個元素的位置。參數-1指定了最后一個元素的位置
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.向數組中尾部或頭部添加、刪除元素的方法,返回數組新的長度/刪除的元素 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 這里不使用任何參數調用join()方法返回的字符串是一樣的。將其每個元素轉成字符串
console.log(['s','c','s'].toLocaleString());//s,c,s
</script>
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轉載于:https://www.cnblogs.com/studyh5/p/9309909.html
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