key一般为NSString，key是惟一的，键值不可为空nil,若是须要一个空值可使用NSNullcode
//初始化一个元素 NSDictionary *dic = [NSDictionary dictionaryWithObject:@"value" forKey:@"key"]; //初始化多个元素 NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys:@"value" ,@"key",@"values2",@"key2",nil]; //以字典初始化 NSDictionary *dic = [NSDictionary dictionaryWithDictionary:otherDic];; //以文件内容初始化 NSDictionary *dic = [NSDictionary dictionaryWithContentsOfFile:path];
经常使用方法it
//总数 NSInteger count = [dic count]; //取值 NSObject *value = [dic objectForKey:@"key"]; //将字典的key转成枚举，用于遍历 NSEnumerator *enum = [dic keyEnumerator]; //获取key的集合 NSArray *keys = [dic allKeys]; //获取全部的value NSArray *values = [dic allValues];