Foundation-NSMutableDictionary

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<span style="font-size:14px;">#import <Foundation/Foundation.h>int main(int argc, const char * argv[]) {    @autoreleasepool {                //可变字典  NSMutableDictionary        //1.初始化        //创建一个空字典        NSMutableDictionary *mDictionary1 = [NSMutableDictionary dictionary];                        //创建有一个键值对的可变字典        NSMutableDictionary *mDictionary2 = [NSMutableDictionary dictionaryWithObject:@"Clown" forKey:@"name"];                //创建多个键值对的可变字典        NSMutableDictionary *mDictionary3 = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"Clown", @"name", @21, @"age", @"GZ", @"address", nil];                //通过另一个字典创建一个字典        NSMutableDictionary *mDictionary4 = [NSMutableDictionary dictionaryWithDictionary:mDictionary3];                NSEnumerator *enumerator = [[mDictionary3 allKeys]objectEnumerator];        NSString *key;        while (key = [enumerator nextObject]) {//            NSLog(@"%@ = %@", key, mDictionary3[key]);        }                        for (NSString *key in mDictionary3.allKeys) {//            NSLog(@"%@ = %@", key, mDictionary3[key]);        }                //可变字典独有的初始化方法        //创建了初始大小为10个键值对的可变字典，同样的这一个参数只是初始的大小，它是用来提高程序的效率的，并没有限制字典的大小，如果继续往里面添加数据，字典的元素个数会继续增加        NSMutableDictionary *mDictionary5 = [NSMutableDictionary dictionaryWithCapacity:10];                //从本地读取字典        NSMutableDictionary *mDictionary6 = [NSMutableDictionary dictionaryWithContentsOfFile:@""];                //从网络读取字典        NSMutableDictionary *mDictionary7 = [NSMutableDictionary dictionaryWithContentsOfURL:[NSURL URLWithString:@""]];                        //操作字典        //增        [mDictionary5 setValue:@"Clown" forKey:@"name"];        [mDictionary5 setValue:@21 forKey:@"age"];                //改(如果原来字典中已有了key这个关键字，那么这次新加的值就会覆盖掉原来关键字(键)key对应的值)        [mDictionary5 setValue:@"Black" forKey:@"name"];                //新语法改        mDictionary5[@"name"] = @"White";                //删除指定key的对象        [mDictionary5 removeObjectForKey:@"name"];                //删除所有key的对象        [mDictionary5 removeAllObjects];                NSLog(@"%@",mDictionary5);                //例子        NSMutableDictionary *mDictionary8 = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"Clown", @"name", @21, @"age", @"GZ", @"address", @"Clown", @"name2", @"Clown", @"name3", nil];        //        NSEnumerator *enumerator1 = [mDictionary8.allValues objectEnumerator];//        NSEnumerator *enumerator2 = [mDictionary8.allKeys objectEnumerator];//        NSString *value1 = [enumerator1 nextObject];//        NSString *key1 = [enumerator2 nextObject];        NSArray *keyD8 = mDictionary8.allKeys;        for (NSString *key in keyD8) {//            NSString *string;                        //因为字典中存在 NSUInteger 的类型，所以对其进行拆包//            if ([mDictionary8[key] isKindOfClass:[NSNumber class]]) {//                int a = [mDictionary8[key] intValue];//                string = [NSString stringWithFormat:@"%d",a];//            }//            else {//                string = mDictionary8[key];//            }                        //等价于以下方法            //通过 value 来把相应的 key 找出来            NSString *string = mDictionary8[key];            if ([string isEqual:@"Clown"]) {                NSLog(@"%@",key);            }        }    }    return 0;}</span>
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