如何从数组中删除除javascript中的第一个元素以外的所有元素

Question

我想从数组中删除除第0个索引处的数组元素以外的所有元素

["a", "b", "c", "d", "e", "f"]

输出应为a

Answer 1

您可以设置数组的length属性。

Answer 2

这是

var input = ['a','b','c','d','e','f'];  
input.splice(1);
console.log(input);

功能。 head也被证明是一项补充功能。

Answer 3

// head :: [a] -> a
const head = ([x,...xs]) => x;

// tail :: [a] -> [a]
const tail = ([x,...xs]) => xs;

let input = ['a','b','c','d','e','f'];

console.log(head(input)); // => 'a'
console.log(tail(input)); // => ['b','c','d','e','f']

Answer 4

您可以使用拼接来实现。

Answer 5

您可以使用切片：

Answer 6

如果要将其保留在https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Global_Objects/Array/slice中，则可以使用array或slice。或再次包装愿望条目。

Answer 7

var Input = ["a","b","c","d","e","f"];  

console.log( [Input[0]] );
console.log( Input.slice(0, 1) );
console.log( Input.splice(0, 1) );

Answer 8

var input = ["a", "b", "c", "d", "e", "f"];

[input[0]];

// ["a"]