function getLastElement(array1, array2, a) { if (a === array1.length) { return array1[array1.length - 1]; } else { return array2[array2.length - 1]; }}
时间: 2024-02-22 22:56:22 浏览: 110
这是一个JavaScript函数,它接受三个参数:array1、array2和a。该函数的作用是判断a的值是否等于array1的长度,如果相等,则返回array1的最后一个元素;否则,返回array2的最后一个元素。
具体来说,函数内部首先使用 `===` 运算符判断a是否等于array1的长度,如果是,则使用数组下标访问符(`[]`)获取array1的最后一个元素并返回;否则,使用同样的方式获取array2的最后一个元素并返回。
下面是一个例子,演示了如何使用该函数:
```javascript
const array1 = [1, 2, 3, 4, 5];
const array2 = ['a', 'b', 'c'];
console.log(getLastElement(array1, array2, 5)); // 输出:5
console.log(getLastElement(array1, array2, 2)); // 输出:'c'
```
在这个例子中,我们定义了两个数组 `array1` 和 `array2`,然后分别传递给 `getLastElement` 函数,并传递了不同的第三个参数a。第一个调用返回了array1的最后一个元素5,因为a的值等于array1的长度;第二个调用返回了array2的最后一个元素'c',因为a的值不等于array1的长度。
相关问题
Given an array of ints, return a new array length 2 containing the first and last elements from the original array. The original array will be length 1 or more.
Sure, here's the solution in Python:
```python
def make_ends(nums):
return [nums[0], nums[-1]]
```
This function takes an input array `nums` and returns a new array containing the first and last elements of the input array. We use the `[0]` index to access the first element of the array, and the `[-1]` index to access the last element of the array.
function $(tag) { let tage = document.querySelectorAll(tag); return tage.length == 1 ? tage[0] : tage; }
This is a JavaScript function that takes a string argument "tag" which represents a tag name (e.g. "div", "p", "ul", etc.).
The function then uses the document.querySelectorAll() method to find all elements in the document that match the specified tag name. This method returns a NodeList, which is an array-like object that contains all the matching elements.
The function then checks if the length of the NodeList is equal to 1. If it is, it returns the first (and only) element in the NodeList. If not, it returns the entire NodeList.
This function essentially allows you to select one or multiple elements in the document using their tag name, and returns them in a convenient and easy-to-use format. It is commonly used in JavaScript programming to manipulate the DOM (Document Object Model) and create dynamic web pages.