{if(hash[arr[i]]==undefined) hash[arr[i]]=1;//如果hash数组中arr[i]对应的元素未定义,说明未重复,则将其放入hash数组中}//结束遍历之后,取出hash数组varback=[];for(back[back.length]inhash);returnback; } console.log(f1([1,2,2,1,4,5])); 运行结果:["1","2","4","5"] 关于执行的效率上,特别当数据增多时,hash数...
Javascript关键字（Keyword）是指在Javascript语言中有特定含义，成为Javascript语法中一部分的那些字，是 J...
What are the common errors in JavaScript? The common errors that developers make while coding in JavaScript include mistaken thinking about how the “this” keyword works, incorrect assumptions about block scoping, and a failure to avoid memory leaks. JavaScript’s evolution over time has left many...
log(array1); // 输出: [1, 2, 3],原始数组没有改变 console.log(array2); // 输出: [4, 5, 6],原始数组没有改变 如上所示,通过调用concat()方法,我们创建了一个新数组newArray,它包含了array1和array2的合并结果。原始数组array1和array2保持不变。 当使用concat()方法时,可以传递一个或多个...
/*遍历:*/for ( var key in obj ) obj[key]; Object完全可以作为一个集合来使用 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12 (1)如果我们要在Array中检索出一个指定的值,我们需要遍历整个数组: var keyword = ; for ( var i=0 ; i < ary.length ; ++i ) ...
constarray_name= [item1,item2, ...]; It is a common practice to declare arrays with theconstkeyword. Learn more aboutconstwith arrays in the chapter:JS Array Const. Example constcars = ["Saab","Volvo","BMW"]; Try it Yourself » ...
age:20}, {name:"王老五",age:21}]letkeyword ="王"letfilPersons = persons.filter((p) =>{returnp.name.indexOf(keyword) !== -1})console.log(filPersons)//结果//Array(2)//>0: {name: '王五', age: 20}//>1: {name: '王老五', age: 21}//>length: 2//>[[Prototype]]: Array(...
a.push(1,2,3); // The push() method adds elements to an array a.reverse(); // Another method: reverse the order of elements // We can define our own methods, too. The "this" keyword refers to the object // on which the method is defined: in this case, the points array from...
Use the new keyword to create an Array object and then assign its indexes some values: let arr = new Array();arr[0] = "foo";arr[1] = "bar";console.log(arr); // ["foo", "bar"] The indexes in an array are integer values, therefore you cannot use the dot operator Object.prope...
slice() Selects part of an array and returns it as a new array. splice() Removes or replaces existing elements and/or adds new elements. To learn more, visit JavaScript Array Methods. More on Javascript Array Create an array using the new keyword. You can also create an array using...