Thefind()method does not change the original array. 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 ...
The find() method returns the value of the first element in an array that pass a test (provided as a function).The find() method executes the function once for each element present in the array:If it finds an array element where the function returns a true value, find() returns the ...
The findIndex() method returns the index of the first element in an array that pass a test (provided as a function).The findIndex() method executes the function once for each element present in the array:If it finds an array element where the function returns a true value, findIndex()...
ThefindIndex()method returns -1 if no match is found. ThefindIndex()method does not execute the function for empty array elements. ThefindIndex()method does not change the original array. Array Find Methods: MethodFinds indexOf()The index of the first element with a specified value ...
6、 Array.map() 你可以使用.map()method 对每个元素执行一个操作(即运行一个函数)并将结果放入一个新数组中。 例如,让我们将一个数字数组转换为一个新的平方数数组: constnums = [1,2,3,4,5];constsquaredNums = nums.map(number=>number*number);...
isArray(): Array.isArray(arr), 检查一个object是不是array,注意,这个method的caller 是Array,而不是arr keys(): arr.keys() 得到这个array的key的iterator。 toString(): arr.toString(), 把arr里所有元素转化成string,用逗号隔开。 join: arr.join(separator), 把array里东西转化成string,用separator隔开,...
The find() method returns the value of the first array element that satisfies the provided test function. Example let numbers = [1, 3, 4, 9, 8]; // function to check even number function isEven(element) { return element % 2 == 0; } // get the first even number let evenNumber...
JavaScript Array.indexof() Method This method is used to find the index of the specified element, which is present in the array. If the element is not found, the method returns -1. conststrings = ["code","damn","web3"];console.log(strings.indexOf('damn'));// 1console.log(strings...
Javascript创建数组的基本方式有两种。第一种是使用Array构造函数。 var colors = new Array(); var colors = new Array(20); var colors = new Array("red","blue","green"); 另外一种是省略掉new符号: var colors = Array(3); var colors = Array("Greg"); ...
6、 Array.map() 你可以使用.map()method 对每个元素执行一个操作(即运行一个函数)并将结果放入一个新数组中。 例如,让我们将一个数字数组转换为一个新的数组: const nums = [1,2,3,4,5]; const squaredNums = nums.map( number => number * number ); ...