NSDictionary使用小结

#import <Foundation/Foundation.h>int main(int argc, const char * argv[]){    @autoreleasepool {        //创建字典        NSDictionary *dic1 = [NSDictionary dictionaryWithObject:@"value" forKey:@"key"];        NSLog(@"dic1 :%@", dic1);                        //创建多个字典        NSDictionary *dic2 = [NSDictionary dictionaryWithObjectsAndKeys:                              @"value1", @"key1",                              @"value2", @"key2",                              @"value3", @"key3",                              @"value4", @"key4",                              nil];        NSLog(@"dic2 :%@", dic2);                        //根据现有的字典创建字典        NSDictionary *dic3 = [NSDictionary dictionaryWithDictionary:dic2];        NSLog(@"dic3 :%@", dic3);                        //根据key获取value        NSLog(@"key3 value :%@", [dic3 objectForKey:@"key3"]);                //获取字典数量        NSLog(@"dic count :%d", dic3.count);                //所有的键集合        NSArray *keys = [dic3 allKeys];        NSLog(@"keys :%@", keys);                //所有值集合        NSArray *values = [dic3 allValues];        NSLog(@"values :%@", values);                                NSMutableDictionary *mutableDic = [[NSMutableDictionary alloc] initWithObjectsAndKeys:                                           @"mvalue1", @"mkey1",                                           @"mvalue2", @"mkey2", nil];        //添加现有的字典数据        [mutableDic addEntriesFromDictionary:dic3];        NSLog(@"mutableDic :%@",mutableDic);                //添加新的键值对象        [mutableDic setValue:@"set1" forKey:@"setKey1"];        NSLog(@"set value for key :%@",mutableDic);                //以新的字典数据覆盖旧的字典数据        [mutableDic setDictionary:dic2];        NSLog(@" set dictionary :%@",mutableDic);                //根据key删除value        [mutableDic removeObjectForKey:@"key1"];        NSLog(@"removeForkey :%@",mutableDic);                //快速遍历        for(id key in mutableDic) {            NSLog(@"key :%@  value :%@", key, [mutableDic objectForKey:key]);        }                //枚举遍历        NSEnumerator *enumerator = [mutableDic keyEnumerator];        id key = [enumerator nextObject];        while (key) {            NSLog(@"enumerator :%@", [mutableDic objectForKey:key]);            key = [enumerator nextObject];        }                        //根据key数组删除元素        [mutableDic removeObjectsForKeys:keys];        NSLog(@"removeObjectsForKeys :%@",mutableDic);                [mutableDic removeAllObjects];        //删除所有元素        NSLog(@"remove all :%@", mutableDic);    }    return 0;}

日志:

dic1 :{    key = value;} dic2 :{    key1 = value1;    key2 = value2;    key3 = value3;    key4 = value4;} dic3 :{    key1 = value1;    key2 = value2;    key3 = value3;    key4 = value4;} key3 value :value3 dic count :4 keys :(    key2,    key3,    key1,    key4) values :(    value2,    value3,    value1,    value4) mutableDic :{    key1 = value1;    key2 = value2;    key3 = value3;    key4 = value4;    mkey1 = mvalue1;    mkey2 = mvalue2;} set value for key :{    key1 = value1;    key2 = value2;    key3 = value3;    key4 = value4;    mkey1 = mvalue1;    mkey2 = mvalue2;    setKey1 = set1;}  set dictionary :{    key1 = value1;    key2 = value2;    key3 = value3;    key4 = value4;} removeForkey :{    key2 = value2;    key3 = value3;    key4 = value4;} key :key4  value :value4 key :key2  value :value2 key :key3  value :value3 enumerator :value4 enumerator :value2 enumerator :value3 removeObjectsForKeys :{} remove all :{}