for(var key of Object.keys(person)){ //使用Object.keys()方法获取对象key的数组 console.log(key+": "+person[key]);//name: coco,age: 22,locate: [object Object] } 示例三: 1 let arr3 = ['a', 'b', 'c']; 2 for (let [index, val] of arr3.entries()) { 3 console.log(index...
log(key) console.log(obj[key]) } } 3 for of for of在Array、Object、Set、Map中都可以使用。 Array Array本质上也是对象,所以我们可以在隐式原型(__proto__)上可以找到定义好的方法。 代码语言:javascript 代码运行次数:0 运行 AI代码解释 for (let key of arr.keys()) { // key是下标 console...
}for(varkey of Object.keys(person)){//使用Object.keys()方法获取对象key的数组console.log(key+": "+person[key]);//name: coco,age: 22,locate: [object Object]} 示例三: 1let arr3 = ['a', 'b', 'c'];2for(let [index, val] of arr3.entries()) {3console.log(index + ':' +va...
一句话概括:for in是遍历(object)键名,for of是遍历(array)键值——for of 循环用来获取一对键值对中的值,而 for in 获取的是 键名。 for in 循环出的是key(并且key的类型是string),for of 循环出的是value。 for of 是es6引新引入的特性,修复了es5引入的for in 的不足。 for of 不能循环普通的对象...
NSString *value1 = [dict objectForKey:@"@theKey"]; NSString *value2 = [dict valueForKey:@"@theKey"]; 1. 2. 3. 4. 5. 6. 7. 8. 9. value1 可以正确取值,但是 value2 取值会直接 crash 掉,报错信息: Terminating app due to uncaught exception ‘NSUnknownKeyException’, reason: ‘...
浅析JavaScript中in操作符(for in/for of)、Object.keys()和Object.getOwnPropertyNames()的区别,ECMAScript将对象的属性分为两种:数据属性和访问器属性。每一种属性内部都有一些特性,这里我们只关注对象属性的[[Enumerable]]特征,它表示是否通过for-in循环返回属性,也
func dictionary(forKey: String) -> [String : Any]? Returns the dictionary object associated with the specified key. func string(forKey: String) -> String? Returns the string associated with the specified key. func stringArray(forKey: String) -> [String]? Returns the array of strings assoc...
然后应该用 for...of 循环 const obj = { a: 1, b: 2, c: 3 } Object.prototype[Symbol.iterator] = function() { const keys = Object.keys(this); let nextIndex = 0; const that = this; function next() { return nextIndex < keys.length ? { value: [keys[nextIndex], that[keys[...
you can use the security identifier (SID) in place of the group name. You can retrieve the SID by runningGet-LocalGroup | Select-Object Name, SID. When you use the SID in place of the group name, it must be preceded by an asterisk (*). In the following example, theAdministratorsgroup...
object The JSObjectRef to test. propertyKey A JSValueRef that contains the property key to use when looking up the property. exception A pointer to a JSValueRef to store an exception in, if any. Pass NULL to discard any exception. Return Value YES if the object has a property with ...