Objective-C 字典的基本用法（NSDictionary和NSMutableDictionary）

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        // insert code here...
        //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 :%lu", 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;
}

NSLog

 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 :{
}