简介: js成员检查方式in、indexOf、includes、inArray 定义用于测试的列表和对象 let list = ["pig", "dog", "cat"]; let obj = { "name": "dog", "age": 12, "sex": "man" }; 方案一、in in操作符针对的是key,而非value, 对于普通的一维数组来说,key是隐藏的 c
text.indexOf("e",5); Try it Yourself » Find the first occurrence of "a": lettext ="Hello world, welcome to the universe."; text.indexOf("a"); Try it Yourself » Description TheindexOf()method returns the position of the first occurrence of a value in a string. ...
Now I would like to have the indexOf the object which hello property is 'stevie' which, in this example, would be 1. 现在我想得到hello属性值是stevie的对象的索引。在这个例子里,它是1 I'm pretty newbie with JavaScript and I don't know if there is a simple method or if I should build...
console.log('dog' in obj); // false 1. 2. 3. 4. 5. 方案二、indexOf indexOf是用于字符串和数组,不能用于对象 console.log(list.indexOf('dog')); // 1 console.log(list.indexOf('apple')); // -1 1. 2. 方案三、includes 同indexOf一样,includes仅能用于字符串和数组 console.log(lis...
字符串同上str1.indexOf('aa')!=-1来判断是够包含 includes与indexOf用法相同,可以用于判断数组/字符串 array('a','b').includes('a')返回值为true array('a','b').includes('')返回值为false in 用来判断一个属性是否属于一个对象,即判断字符串是否在keys中 ...
letresult = text.lastIndexOf("Planet"); Try it Yourself » More examples below. Description ThelastIndexOf()method returns the index (position) of the last occurrence of a specified value in a string. ThelastIndexOf()method searches the string from the end to the beginning. ...
Object inherits the hasOwnProperty method. This method can be used to determine whether an object has the specified property as a direct property of that object; unlike the in operator, this method does not check down the object's prototype chain ...
<!DOCTYPE html> Title let arr = ['a','b','c']; console.log("1:","a" in arr); console.log("2:",arr.indexOf('a')); console.log("3:",arr.includes('a')); 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17...
[Microsoft.JScript.JSFunction(Microsoft.JScript.JSFunctionAttributeEnum.HasThisObject, Microsoft.JScript.JSBuiltin.String_indexOf)] public static int indexOf(object thisob, object searchString, double position); Parameters thisob Object The object that this method is acting upon. searchString Object...
+ +```Python +def login(request: HttpRequest) -> HttpResponse: + hint = '' + if request.method == 'POST': + username = request.POST.get('username') + password = request.POST.get('password') + if username and password: + password = gen_md5_digest(password) + user = User....