1. 檢測陣列 array.isarray()
var arr =[1
,2,3
];console.
log(array.
isarray
(arr)
)//true
var arr1 =
["a"
,"b"
,"c"];
arr1.
push
("d");
console.
log(arr1)
//["a", "b", "c", "d"]
var arr1 =
["a"
,"b"
,"c"];
arr1.
pop();
console.
log(arr1)
//["a", "b"]
var arr1 =
["a"
,"b"
,"c"];
arr1.
unshift
("d");
console.
log(arr1)
//["d", "a", "b", "c"]
var arr1 =
["a"
,"b"
,"c"];
arr1.
shift()
;console.
log(arr1)
//["b", "c"]
var arr1 =
["a"
,"b"
,"c"];
console.
log(arr1.
join
('|'))
//a|b|c
var arr =[1
,2,3
];console.
log(arr.
reverse()
)// [3,2,1]
var arr =[1
,2,3
];var arr1 =[4
,5,6
];console.
log(arr.
concat
(arr1)
)//[1, 2, 3, 4, 5, 6]
var arr =
['aa'
,'bb',11
];console.
log(arr.
slice(0
));//['aa','bb',11]
var arr =
['aa'
,'bb',11
];arr.
splice(1
,1);
//開始的索引，要刪除的個數
console.
log(arr)
;//["aa", 11]
var arr =
['aa'
,'bb',11
];arr.
splice(0
,1,'cc');
console.
log(arr)
;//["cc", "bb", 11]
var arr =
['aa'
,'bb',11
];arr.
splice(2
,0,'dd');
//在下標為2的元素的前面插入
console.
log(arr)
;//["aa", "bb", "dd", 11]
var arr =[1
,2,3
];console.
log(arr.
indexof(2
))//1var arr1 =[1
,2,3
,2];
console.
log(arr1.
indexof(2
,2))
//3
includes方法:
var arr =[1
,2,3
];arr.
includes(1
)//true
14. 轉換方法
15.find & findindex
//1.
let arr =[22
,33,44
]let res = arr.
find
((item,index)
=>
)alert
(res)
//33
//2.
let arr =[22
,33,44
]let res = arr.
find
((item,index)
=>
)alert
(res)
//undefined
//1.
let arr =[22
,33,44
]let res = arr.
findindex
((item,index)
=>
)alert
(res)
//0//2.
let arr =[22
,33,44
]let res = arr.
findindex
((item,index)
=>
)alert
(res)
//-1
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