key一般爲NSString,key是惟一的,鍵值不可爲空nil,若是須要一個空值可使用NSNullcode
//初始化一個元素 NSDictionary *dic = [NSDictionary dictionaryWithObject:@"value" forKey:@"key"]; //初始化多個元素 NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys:@"value" ,@"key",@"values2",@"key2",nil]; //以字典初始化 NSDictionary *dic = [NSDictionary dictionaryWithDictionary:otherDic];; //以文件內容初始化 NSDictionary *dic = [NSDictionary dictionaryWithContentsOfFile:path];
經常使用方法it
//總數 NSInteger count = [dic count]; //取值 NSObject *value = [dic objectForKey:@"key"]; //將字典的key轉成枚舉,用於遍歷 NSEnumerator *enum = [dic keyEnumerator]; //獲取key的集合 NSArray *keys = [dic allKeys]; //獲取全部的value NSArray *values = [dic allValues];