//數(shù)組直接量形式 創(chuàng)建數(shù)組 []
var arr = [1, 2, 3, 4, 5];
//.length 可以獲取到數(shù)組的長度
console.log(arr.length);

//通過構(gòu)造函數(shù)形式 創(chuàng)建數(shù)組 new Array ()
//new Array(5) 代表創(chuàng)建的數(shù)組長度為5
var arr = new Array(5);
// 結(jié)果是5
console.log(arr.length);

//數(shù)組的讀取丰辣、修改、添加、刪除
var ar = [1, 2, 3, 4, 5];
//用下標讀取數(shù)組的值,下標從0開始   數(shù)組名[下標] 
console.log(ar[0]); // 1
//用下標修改數(shù)組的值 數(shù)組名[下標] = ‘需要修改的數(shù)組值’
ar[0] = 'hello';
console.log(ar[0]); // hello
//用下標添加數(shù)組的值 數(shù)組名[添加數(shù)組下表] = ‘添加數(shù)組值’
ar[6] = 'world';
console.log(ar[6]); //world
//用下標刪除數(shù)組的值 delete 數(shù)組名[需要刪除的數(shù)組下標]
delete ar[1];
console.log(ar) //[ 'hello', , 3, 4, 5, , 'world' ]

//數(shù)組的首尾添加刪除方法 .push .pop .unshift .shift
var p = ['b', 'c', 'd'];
//數(shù)組名.push('數(shù)組尾部添加的值') 在數(shù)組末尾添加值
p.push('a');
console.log(p); //[ 'b', 'c', 'd', 'a' ]
//數(shù)組名.pop() 彈出數(shù)組末尾的值
p.pop();
console.log(p); //[ 'b', 'c', 'd' ]

//數(shù)組名.unshift(數(shù)組首添加值)
p.unshift(1, 2, 3);
console.log(p); //[ 1, 2, 3, 'b', 'c', 'd' ]
//數(shù)組名.shift() 彈出數(shù)組首位的值
p.shift();
console.log(p);



//通過for循環(huán)遍歷下標連續(xù)的數(shù)組
var larr = ['a', 'b', 'c', 'd', 'e'];
var len = larr.length;
for (var i = 0; i < len; i++) {
    console.log(larr[i]);
};
//通過for in 循環(huán)遍歷
var la = [1, 2, 3, 4, 5, 6, 7];
for (var i in la) {
    console.log(la[i])
};
//通過forEach 循環(huán)遍歷
var forarr = ['marshll', 'mesa', 'fender'];
forarr.forEach(function(x) {
    console.log(x);
})

//自定義函數(shù)用forEach方法遍歷
function Testarr(element, index, array) {
    console.log('數(shù)組為:' + array);
    console.log('索引：' + index + '值' + element);
};
forarr.forEach(Testarr);


//.join('分隔符') 指定分隔符分隔數(shù)組
var y = ['aa', 'bb', 'cc'];
var w = y.join('-');
console.log(w); //aa-bb-cc
//.reverse() 反轉(zhuǎn)數(shù)組
var f = y.reverse();
console.log(f); //[ 'cc', 'bb', 'aa' ]
//.sort() 排序
var s = [1, 4, 3, 2, 5];
var ss = s.sort();
console.log(ss);
//數(shù)組名.concat(添加的值) 組成新數(shù)組
var c = s.concat(6, 7, 8, 9);
console.log(c); //[ 1, 2, 3, 4, 5, 6, 7, 8, 9 ]

//數(shù)組名.slice(起始值崭捍，終止值) 獲取數(shù)組中一段數(shù)值
var e = [1, 2, 3, 4, 5, 6, 7, 8];
var sli = e.slice(2, -3);
console.log(sli);

//數(shù)組名.splice(起始值预伺，終止值延窜，’替換值‘)  從數(shù)組中取出數(shù)值用替換值補上
var h = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0];
var sp = h.splice(0, 3, '!', 'b', 'c', 'd');
console.log(h);