在 JavaScript 中使用 splice 函数

Question

拼接函数不能写在console.log里面？？我都试过了这就是我试过的-

const arr1 = ["a","b","c","d","e","f"];
console.log(arr1.splice(1,4,"HI"));

此代码的输出= ['a', 'HI', 'f' ]

const arr1 = ["a","b","c","d","e","f"];
arr1.splice(1,4,"HI");`enter code here`
console.log(arr1);

此代码的输出 = ['b'、'c'、'd'、'e']`

有什么区别？

Answer 1

在第一个示例中，您正在记录 splice（包含已删除元素的数组）的 return 值 。

在第二个示例中，您正在记录 变异数组 。

const arr1 = ["a", "b", "c", "d", "e", "f"];
const return_value = arr1.splice(1, 4, "HI");
console.log({
  return_value,
  arr1
});

Answer 2

日志显示 splice 函数 返回的内容 ，这是一个已删除项目的数组。您似乎想查看原始数组的 new 内容，这不是 splice returns 的内容，因此您必须单独显示它。

arr1.splice(1,4,"HI")
console.log(arr1);

实例：

const arr1 = ["a","b","c","d","e","f"];
arr1.splice(1,4,"HI");
console.log(arr1);

或者如果你真的想要单行，你可以滥用逗号运算符：

console.log((arr1.splice(1,4,"HI"), arr1)); // But please don't do this ;-)

实例：

const arr1 = ["a","b","c","d","e","f"];
console.log((arr1.splice(1,4,"HI"), arr1)); // But please don't do this ;-)

use of splice function in JavaScript