// Function to check if an array contains a specific elementfunctioncontains(arr,element){// Iterate through the arrayfor(vari=0;i<arr.length;i++){// Check if the current element is equal to the target elementif
使用filter(注意:array.filter(e=>e==x).length > 0等效于array.some(e=>e==x)但some更有效) functioncontains(arr, val){returnarr.filter((item)=>{returnitem == val }).length >0;} 方式三:array.indexOf array.indexOf此方法判断数组中是否...
3、数组的位置是ECMAScript5为数组实例新增的,支持的浏览器有IE9+,Firefox,Safari,Opera,Chrome 方式四:array.includes array.includes(searchElement[, fromIndex]) 此方法判断数组中是否存在某个值,如果存在返回 true,否则返回false。 它可以像这样使用: [1, 2, 3].includes(2); // true [1, 2, 3].incl...
objArray.sort(comparefn)--- 根据comparefn定义的大小比较函数,对一个数组进行排序。函数comparefn必须接受两个参数element1,element2,如果需要需要element1排在element2之前,应该返回一个负数;如果需要element1排在element2之后,应该返回一个正数,如果两个数平等对待(即保持原有顺序)则返回0。当省略comparefn时,则元素...
Theincludes()method checks if anarraycontains a specified element or not. Example // defining an arrayletlanguages = ["JavaScript","Java","C"]; // checking whether the array contains 'Java'letcheck = languages.includes("Java"); console.log(check);// Output: true ...
Theincludes()method returnstrueif an array contains a specified value. Theincludes()method returnsfalseif the value is not found. Theincludes()method is case sensitive. Syntax array.includes(element,start) Parameters ParameterDescription elementRequired. ...
functionisInArray(array, element){returnarray.includes(element);} 23、反转字符串中单词的顺序: functionreverseWords(str){returnstr.split(' ').reverse().join(' ');} 24、检查字符串是否以特定子字符串结尾: functionendsWith(str, substring){returnst...
Array length Returns the length (size) of an array Array toString() Converts an array to a comma separated string of values Array at() Returns an indexed element from an array Array join() Joins all array elements into a string Array pop() Removes the last element from an array Array ...
find() Returns the first value of the array element that passes a given test. findIndex() Returns the first index of the array element that passes a given test. forEach() Calls a function for each element. includes() Checks if an array contains a specified element. sort() Sorts the e...
console.log([]instanceofArray);//truefunctionStudent(){}//定义构造函数vartom=newStudent();//实例化一个Student对象console.log(tominstanceofStudent);//trueconsole.log(tominstanceofObject);//trueconsole.log(tominstanceofNumber);//false 输出结果如图1-3所示。