如何切片数组JavaScript中的每个数组

Question

例如此数组

'APP_DIRS': True

我想切片每个数组以使用slice（0,3）生成一个像这样的新数组

DIRS

Answer 1

使用forEach（）循环或map（）并将切片的原始数组项简单地推入第二个数组中。

var array=  [
    [1,"dataA","dataB","dataC","dataD"],
    [2,"dataA","dataB","dataC","dataD"],
    [3,"dataA","dataB","dataC","dataD"],
    [4,"dataA","dataB","dataC","dataD"]
    ];
    

var resultSecondArray= [];

array.forEach (function(arr){
  resultSecondArray.push(arr.slice(0,3));
})

console.log(resultSecondArray); // gives [[1, "dataA","dataB"],[2, "dataA","dataB"],[ 3, "dataA", "dataB"],[ 4,"dataA", "dataB"]]

使用map（）获得相同的结果

let array=  [
    [1,"dataA","dataB","dataC","dataD"],
    [2,"dataA","dataB","dataC","dataD"],
    [3,"dataA","dataB","dataC","dataD"],
    [4,"dataA","dataB","dataC","dataD"]
    ];
    

let resultSecondArray= array.map(arr => arr.slice(0,3));

console.log(resultSecondArray); // gives [[1, "dataA","dataB"],[2, "dataA","dataB"],[ 3, "dataA", "dataB"],[ 4,"dataA", "dataB"]]