To check if any element is present in the array, we can find the index of that element and check ifindex >= 0, then the element exists, else it doesn’t. The lastIndexOf method This method returns the index of the last occurrence of matched element in the array. This method searches...
if ( this [i] == element) { return true ; } } return false ; } 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 用法如下: var arr=new Array(["b",2,"a",4,"test"]); 1. arr.in_array('test');//判断 test 字符串是否存在于 arr 数组中,存在返回true 否则false,此处...
Example 1: Using findIndex() method // function that returns even numberfunctionisEven(element){returnelement %2==0; }// defining an array of integersletnumbers = [1,45,8,98,7]; // returns the index of the first even number in the arrayletfirstEven = numbers.findIndex(isEven); conso...
functionisBigEnough(element) {returnelement >= 15; }varret1 = [12, 5, 8, 130, 44].findIndex(isBigEnough); console.log(ret1);//index of 4th element in the Array is returned,//so this will result in '3'varobjArr = [{id:1, name:'jiankian'}, {id:23, name:'anan'}, {id:...
functionisBigEnough(element){returnelement>=15;}[12,5,8,130,44].findIndex(isBigEnough);// index of 4th element in the Array is returned,// so this will result in '3' 另请参见find()方法,它返回数组中找到的元素的值,而不是其索引。
如果你需要找到一个元素的位置或者一个元素是否存在于数组中,使用Array.prototype.indexOf()或Array.prototype.includes()。 语法 1 arr.find(callback[, thisArg]) 参数 callback在数组每一项上执行的函数,接收 3 个参数: element当前遍历到的元素。
function isPrime(element, index, array) { var start = 2; while (start <= Math.sqrt(element)) { if (element % start++ < 1) { return false; } } return element > 1; } console.log([4, 6, 8, 12].find(isPrime)); // undefined, not found console.log([4, 5, 8, 12].find(is...
在这个示例中,我们定义了一个名为findElementInNestedArray的函数,该函数接受一个嵌套数组和要查找的元素作为参数。我们使用两个嵌套的for循环遍历嵌套数组,并在找到元素时返回其索引。如果元素不存在于数组中,则返回null。 请注意,这个示例仅适用于二维数组。如果你需要在更高维度的数组中查找元素,你需要相应...
In an array every element appears twice except for one. Write a JavaScript program to find the non-repeated element in an array using bit manipulation. Test Data: ([1]) -> 1 ([1, 2, 3]) -> 0 [All elements are non- repeated] ...
Since array indexing starts from 0, we need to reference the array with index animals.length-1. For example- const lastElement = animals[animals.length-1];Code language: JavaScript (javascript) lastElement consists of the last element of the array animals. Using slice() method When we want...