let arr = [1, 3, 6, 5, 7, 6]; 方法1、indexOf方法 let index1 = arr.indexOf(6); console.log(index1);//2 1. 2. 方法2、lastIndexOf方法 从右至左查找,找到返回索引,找不到返回-1 let index2 = arr.lastIndexOf(6); console.log(index2);//5 1. 2. 方法3、includes方法 从左往...
lastIndexOf() 方法可返回一个指定的字符串值最后出现的位置,在一个字符串中的指定位置从后向前搜索。 stringObject.indexOf(searchvalue,fromindex)该方法将从头到尾地检索字符串 stringObject,看它是否含有子串 searchvalue。开始检索的位置在字符串的 fromindex 处或字符串的开头(没有指定 fromindex 时)。如果找到...
下面,我们简单来实现一下.findLast()和.findLastIndex(): .findLast() 代码语言:javascript 代码运行次数:0 运行 AI代码解释 functionfindLast(arr,callback,thisArg){for(letindex=arr.length-1;index>=0;index--){constvalue=arr[index];if(callback.call(thisArg,value,index,arr)){returnvalue;}}returnun...
The findLastIndex() method executes a function for each array element.The findLastIndex() method returns the index (position) of the last element that passes a test.The findLastIndex() method returns -1 if no match is found. The findLastIndex() method does not execute the function for...
JavaScript built-in: Array: findLast Global usage 94.53% + 0% = 94.53% IE ❌ 6 - 10: Not supported ❌ 11: Not supported Edge ❌ 12 - 96: Not supported ✅ 97 - 134: Supported ✅ 135: Supported Firefox ❌ 2 - 103: Not supported ✅ 104 - 136: Supported ✅ 137: ...
Array Find Methods: MethodFinds indexOf()The index of the first element with a specified value lastIndexOf()The index of the last element with a specified value find()The value of the first element that passes a test findIndex()The index of the first element that passes a test ...
Vue Js lastindexOf Method : The last index (position) of a given value is returned by the lastIndexOf() method. The search defaults to beginning at the last element and ending at the first. Negative start values begin counting with the previous
1.基本知识点 //创建一个对象并初始化它 var preInitArray = new Array("First Item", "Second...
Array.prototype.indexOf() 需要一个 值 作为第一个参数。这使得在 原始类型(如字符串、数字或布尔值)数组中查找索引成为一个不错的选择。 Array.prototype.findIndex() 期望回调 作为第一个参数。如果您需要具有非原始类型(例如对象)的数组中的索引,或者您的查找条件比值更复杂,请使用此选项。 有关这两种情况的...
//Create a function that finds all animals in the array animals starting with the letter s. let sNameAnimals = []; let sIndex = animals.findIndex(animal => animal[0] === 's'); let numOfAnimals = animals.length while (sIndex !== -1){ ...