JavaScript Array indexOf() 方法JavaScript Array 对象实例 查找数组中的 "Apple" 元素: var fruits = ["Banana", "Orange", "Apple", "Mango"]; var a = fruits.indexOf("Apple"); a 结果输出: 2 以上输出结果意味着 "Apple" 元素位于数组中的第 3 个位置。 尝试一下 » ...
JavaScript Array 对象方法太多了,短时间内记不住的,可以每天学几个日积月累,来学习几个常用的方法吧 ! 1. some() 检测数组中的元素是否满足指定条件 用于检测数组中的元素是否满足指定条件,比如: 判断数组中是否存在大于 10 的数组元素 该方法会依次执行数组的每个元素,如果有一个元素满足条件,则返回 true , ...
JavaScript Array lastIndexOf() 方法JavaScript Array 对象实例 查找数组元素 "Apple"出现的位置: var fruits = ["Banana", "Orange", "Apple", "Mango"]; var a = fruits.lastIndexOf("Apple"); a 输出结果: 2 以上实例输出结果意味着 "Apple" 位于数组中的第 2 个位置. 尝试一下 » ...
前言 1. some() 检测数组中的元素是否满足指定条件 2. filter() 过滤掉数组中不满足指定条件的值 3. indexOf() 判断一个元素是否在数组中存在 前言 JavaScript Array 对象方法太多了,短时间内记不住的,可以每天学几个日积月累,来学习几个常用的方法吧 ! 1. some() 检测数组中的元素是否满足指定条件 用于...
Returns the first index at which a given element can be found in the array, or -1 if it is not present. Method of Array Implemented in JavaScript 1.6 ECMAScript Edition ECMAScript 5th Edition Syntax array.indexOf(searchElement[, fromIndex]) Parameters searchElement Element to locate in the ...
ThelastIndexOf()method returns the last index (position) of a specified value. ThelastIndexOf()method returns -1 if the value is not found. ThelastIndexOf()starts at a specified index and searches from right to left (from the given postion to the beginning of the array). ...
The indexOf() method returns the first index (position) of a specified value.The indexOf() method returns -1 if the value is not found.The indexOf() method starts at a specified index and searches from left to right (from the given start postion to the end of the array)....
A: Yes, JavaScript arrays also have an indexOf() method that works similarly to the string method. It searches for the first occurrence of a specified element and returns its index or -1 if the element is not found in the array. Q: Is there a case-insensitive version of the indexOf(...
in operator// b. Let kPresent be the result of calling the// HasProperty internal method of o with argument Pk.// This step can be combined with c// c. If kPresent is true, then// i. Let elementK be the result of calling the Get// internal method of o with the argument ...
what values are returned when a search is successful vs when it's unsuccessful. Then we move onto a technique that shows how to use the return value to create a boolean flag that can be checked easily. We end by filtering 1 array based on the existence of a value in awhitelistarray. ...