根據來自另一個表的索引獲取數組的元素

Question

我有兩個數組。
一個與我的數據：

var tab1 = ["one","two","three","four","five","six","seven","eight","nine","ten","eleven","twelve","thirteen","fourteen","fifteen","sixteen","seventeen","eighteen","nineteen","twenty"];

另一個帶有 int：

var tab2 = [1,4,5,8,12,15,18];

我想放入tab1中的tab3值，這些值具有來自tab2值的索引。
我曾嘗試使用一些indexOf // findIndexe
做到這一點的最佳方法是什么？

Answer 1

您可以將tab2數組映射到名為tab3的新數組中

 const tab1 = [ "one","two","three","four","five","six","seven", "eight","nine","ten","eleven","twelve","thirteen","fourteen", "fifteen","sixteen","seventeen","eighteen","nineteen","twenty" ]; const tab2 = [1,4,5,8,12,15,18]; const tab3 = tab2.map(index => tab1[index]) console.log(tab3)

問題要求索引。 但是，如果所需的答案是數字的實際字符串表示形式，則您將在列表中搜索index-1項。

 const tab1 = [ "one","two","three","four","five","six","seven", "eight","nine","ten","eleven","twelve","thirteen","fourteen", "fifteen","sixteen","seventeen","eighteen","nineteen","twenty" ]; const tab2 = [1,4,5,8,12,15,18]; const tab3 = tab2.map(index => tab1[index -1]) console.log(tab3)

Answer 2

使用Array.map() ：

 const tab1 = ["one","two","three","four","five","six","seven","eight","nine","ten","eleven","twelve","thirteen","fourteen","fifteen","sixteen","seventeen","eighteen","nineteen","twenty"]; const tab2 = [1,4,5,8,12,15,18]; const tab3 = tab2.map(num => tab1[num - 1]); console.log(tab3);

Answer 3

讓我們迭代包含索引的數組並將數據的值對應於索引。

tab2.forEach(i => { 
    tab3.push(tab1[i]) 
})

Answer 4

你可以通過使用對象來做到這一點，因為 js 中沒有索引數組。

var tab1 = ["one","two","three","four","five","six","seven","eight","nine","ten","eleven","twelve","thirteen","fourteen","fifteen","sixteen","seventeen","eighteen","nineteen","twenty"];

var tab2 = [1,4,5,8,12,15,18];
var tab3 = {};
tab2.forEach((val) => {
    tab3[val] = tab1[val];
})

console.log(tab3);

當然，tab3 的鍵和值不會匹配，因為 js 數組是從零開始的。