lst = ["pig", "dog", "cat"]obj = {"name": "dog","age": 12,"sex": "man"}# 作用于数组print('dog' in lst) # Trueprint('apple' in lst) # False# 作用于对象print('name' in obj) # Trueprint('dog' in obj) # False 参考 js如何判断数组含有某值,in/includes/inArray/indexOf...
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...
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. ...
=-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 let arr=[“a”,“b”,“c”]; let arr2={“a”:“aaa”,“b”:...
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 ...
indexOf(2); // 0 array.indexOf(7); // -1 array.indexOf(9, 2); // 2 array.indexOf(2, -1); // -1 array.indexOf(2, -3); // 0 你没法使用 indexOf() 来搜索 NaN。 jsCopy to Clipboard const array = [NaN]; array.indexOf(NaN); // -1 ...
JavaScript1.6新特性系列之 indexOf Summary Returns the first index at which a given element can be found in the array,or -1 if it is not present. Method of Array Implemented in Jav ...
[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....