iOS开发学习第十八课——字典 和 集合

        //字典, 用来存储具有一一对应关系的数据,例如,name:XiaoLong  price:30
        //本质上也是一个大容器,用来存储数据
             //value必须为对象, key一般为NSString

       

#import

int main(int argc, const char * argv[]) {

    @autoreleasepool {        

        //1.使用初始化方法创建字典对象(最常用的创建字典对象的方法)  value在前,key在后,在创建的时候不要有两个及两个以上的 相同的 key,一个key对应一个value,如果具有多个相同的value是不影响的
        NSDictionary *dic = [[NSDictionary alloc]initWithObjectsAndKeys:@"XiaoLong",@"name",@"m",@"sex",@"18",@"age",nil];
        NSLog(@"dic = %@",dic);
       
        //第二种创建字典对象的方式
        //对于这种方法,会有数组参数,前面是传入values,后面是传入keys,而且values与keys一一对应的
        NSDictionary *dic2 = [[NSDictionary alloc] initWithObjects:[NSArrayarrayWithObjects:@"DouDou",@"Frank",@"AnLong", nil] forKeys:[NSArrayarrayWithObjects:@"D",@"F",@"A", nil]];
        NSLog(@"%@",dic2);
       
        //第三种方法创建字典对象 便利构造器创建
        NSDictionary *dic3 = [NSDictionary dictionaryWithObjectsAndKeys:@"XiXi",@"X",@"DouDou",@"D",@"DiaoSi",@"S", nil];
        NSLog(@"%@",dic3);
       
        //求字典中元素的个数,即键值对(key - value)的个数
        NSUInteger dicCount = [dic3 count];
        NSLog(@"%lu",dicCount);
       
        //如何取到key对应的value的值
        NSString *DValue = [dic3 objectForKey:@"D"];
        NSLog(@"DValue = %@",DValue);
        NSString *nameValue = [dic objectForKey:@"name"];
        NSLog(@"nameValue = %@",nameValue);
        //求所有的key的值
        NSArray *dic3Keys =[dic3 allKeys];
        NSLog(@"dic3Keys = %@",dic3Keys);
        NSArray *dicKeys = [dic allKeys];
        NSLog(@"keys = %@",dicKeys);
       
        //求所有的values
        NSArray *values = [dic3 allValues];
        NSLog(@"%@",values);
       
        //for in 遍历字典 实质上遍历得到的是keys
        NSMutableArray *allkeys = [NSMutableArray arrayWithCapacity:1];
        //设置一个数组,用来存储所有的value
        NSMutableArray *allValues = [NSMutableArray arrayWithCapacity:1];
        for (id obj in dic) {
            //遍历词典得到的是keys
            [allkeys addObject:obj];
            //通过keys,得到的是values
            //将得到的value一一添加到数组当中
            NSString *value = [dic objectForKey:obj];
            [allValues addObject:value];
        }
        NSLog(@"allkeys = %@",allkeys);
        NSLog(@"allvalues = %@",allValues);
       
       
        //可变字典
        NSMutableDictionary *mutDic = [[NSMutableDictionary alloc]initWithCapacity:1];
        NSLog(@"mut Dic = %@",mutDic);
        //(1)添加键值对(key - value)
        //setObject:forKey  如果我们新添加的键值对此时字典里不存在这个key值的话,则添加这个新的键值对,如果已经存在了key值的话,则会覆盖修改此key值对应value值
        [mutDic setObject:@"ChenWeiHong" forKey:@"C"];
        NSLog(@"mutDic = %@",mutDic);
        [mutDic setObject:@"SongXiaoLong" forKey:@"S"];
        NSLog(@"mutDic = %@",mutDic);
        [mutDic setObject:@"DongRongJun" forKey:@"D"];
        NSLog(@"mutDic = %@",mutDic);
        [mutDic setObject:@"MingGe" forKey:@"M"];
        NSLog(@"mutDic = %@",mutDic);
        //(2)移除键值对,根据key来移除
        [mutDic removeObjectForKey:@"S"];
        NSLog(@"mutDic = %@",mutDic);
        //(3)移除数组,根据传入的key值数组,同时删除多个键值对
        [mutDic removeObjectsForKeys:[NSArray arrayWithObjects:@"C",@"D",nil]];
        NSLog(@"mutDic = %@",mutDic);
        //(4)移除所有键值对  移除所有元素,字典对象所占的空间还是存在的
        [mutDic removeAllObjects];
        NSLog(@"mutDic = %@",mutDic);
       
       
        //集合 NSSet 集合也是一个容器,特点:无序性,互异性
        //也就是说,集合里面的元素互不相同,而且元素必须是对象类型
        NSSet *set = [[NSSet alloc]initWithObjects:@"aa",@"bb",@"cc",@"dd",@"ff",@"dd", nil];
        NSLog(@"%@",set);
        //求元素个数
        NSUInteger setCount = [set count];
        NSLog(@"%lu",setCount);
        //获取集合里的元素  anyObject 获取任意一个元素(对象)
        NSString *element = [set anyObject];
        NSLog(@"%@",element);
        //可变集合
        NSMutableSet *mutSet = [[NSMutableSet alloc] initWithCapacity:1];
        //添加集合元素
        [mutSet addObject:@"11"];
        [mutSet addObject:@"43"];
        [mutSet addObject:@"34"];
        [mutSet addObject:@"43"];//如果添加已有的元素,则不会添加
        //也可以从数组里面添加
        [mutSet addObjectsFromArray:[NSArrayarrayWithObjects:@"ew",@"dd",@"fd",@"fs", nil]];
        NSLog(@"%@",mutSet);
        //删除元素
        [mutSet removeObject:@"dd"];
        NSLog(@"%@",mutSet);
        //计数集合
        NSCountedSet *countedSet = [[NSCountedSet alloc]initWithObjects:@"aa",@"bb",@"cc",@"dd",@"ff",@"dd", nil];
        //计算dd的个数
        NSUInteger ddCount = [countedSet countForObject:@"dd"];
        NSLog(@"ddCount = %lu",ddCount);
       
        
       
        //字面量 --- "语法糖"/"笑脸语法"
        //1.如何将C语言当中的字符串常量快速转化为OC字符串对象
        //第一种方法
        NSString *str = [[NSString alloc] initWithFormat:@"Hello"];
        //第二种方法
        NSString *str1 = @"Hello!";
       
        //2.如何将C语言里的基本数据类型快速地转化为OC当中的对象类型(NSNumber对象)
        //第一种方法
        int a = 10;
        NSNumber *numA = [NSNumber numberWithInt:a];
        //第二种方法
        int b = 8;
        NSNumber *numB = @(b);
        NSNumber *numB1 = @8;
        float c = 10.5;
        NSNumber *numC = @(c);
        BOOL d = YES;
//        NSNumber *bool = @(d);
       
        //3.如何快速创建不可变数组对象
        NSArray *array = [[NSArray alloc]initWithObjects:@"xiaolong",@"xiaoming",@"xiaoan",@"xiaoyu", nil];
        NSArray *array1 = @[@"xiaolong",@"xiaoming",@"xiaoan",@"xiaoyu"];
        NSLog(@"%@",array);
       
        //在使用语法糖的时候,将基本数据类型转化成OC中的对象类型,
        NSArray *arr2 = @[@"8",@"24",@"5",@"33"];
       
       
        //4.如何快速创建可变数组对象
        NSMutableArray *mutArr = [NSMutableArrayarrayWithObjects:@"xiaolong",@"xiaoming",@"xiaoan",@"xiaoyu", nil];
        //可变数组需要加 mutableCopy ,将不可变数组转化为可变数组
        NSMutableArray *mutArr1 = [@[@"xiaolong",@"xiaoming",@"xiaoan",@"xiaoyu"]mutableCopy];
        //取到数组中的某一个元素
        NSString *arrIndex = [mutArr objectAtIndex:2];
        NSString *arrIndex2 = [mutArr objectAtIndex:2];
       
       
        //5.如何快速创建一个不可变字典
        NSDictionary *dic5 = [[NSDictionary alloc]initWithObjectsAndKeys:@"XiaoLong",@"name",@"m",@"sex", @"18",@"age",nil];
        NSDictionary *dic6 = @{@"name":@"XiaoLong",@"sex":@"m",@"age":@"18"};
       
       
        //6.创建一个可变字典
        NSMutableDictionary  *mutDic6 = [@{@"name":@"XiaoLong",@"sex":@"m",@"age":@"18"} mutableCopy];
        //如何通过key值得到相应的value值

        NSString *valueOfKey = [mutDic6 objectForKey:@"name"];

        NSString *valueOfKey1 = mutDic6[@"name”];

       
    }
    return 0;

}