(有码)字典

字典

不可变字典:key和value是一种映射关系，字典中不能添加重复的key

创建字典

NSDictionary *dict = @{@"key":@"value"};

取值

NSString *string = [dict objectForKey:@"name"]; //通过key取得value

NSString *string = dict[@"key"]; //通过key取得value

NSArray *array = [dict allKeyForObject:@"value"]; //找出所有对应的key

NSArray *array = [dict allKeys]; //获取所有的key

NSArray *array = [dict allValues]; //获取所有value

字典遍历

for(id obj in dict){

NSLog(@"%@",obj); //遍历字典=打印key

}

for(id obj in dict.allValues){

NSLog(@"%@",obj); //遍历所有的value

}

可变字典

可变字典创建 NSMutableDictionary *mutableDict = [[NSMutableDictionary alloc]init];

将字典存入可变字典

[mutableDict addEntriesForDictionary:dict];

添加一对一的值

[mutableDict setObject:@170 forKey:@"height"];

删除元素

[mutableDict removeObjectForKey:@"height"]; //删除key

[mutableDict setValue:nil forKey:@"name"]; //删除value

从其他字典中添加键值对

[nutableDict addEntriesFromDictionary:dict];

用set给数组去重(不重复，无序)

array = [[NSSet setWithArray:array]allObjects];

例：

NSSet *set = [NSSet setWithObject:@"1", @"2", @"2", @"4", @"5"];

NSLog(@"%@",set); //打印结果  1 4 2 5(无序，不重复)