OC中的集合类 NSSarray、NSSet、NSDictionary

NSArray 用于对象有序集合（相当于是数组）
NSSet 用于对象无序集合
NSDictionary用于键值映射
以上三种集合类是不可变的（一旦初始化后，就不能改变）

以下是对应的三种可变集合类(这三种可变集合类是对应上面三种集合类的子类)：
NSMutableArray
NSMutableSet
NSMutableDictionary

注：这些集合类只能收集cocoa对象（NSOjbect对象），如果想保存一些原始的C数据（例如，int, float, double, BOOL等），则需要将这些原始的C数据封装成NSNumber类型的，NSNumber对象是cocoa对象，可以被保存在集合类中。

 NSArray

初始化NSArray

NSArray *arry=[NSArray arrayWithObjects:@"asd",@"bgh",@"cui",@"dqe", nil];

判断集合的元素个数

NSArray *arry=[NSArray arrayWithObjects:@"asd",@"bgh",@"cui",@"dqe", nil];
NSLog(@"%ld",arry.count);

获取指定索引位置的集合元素

NSArray *arry=[NSArray arrayWithObjects:@"asd",@"bgh",@"cui",@"dqe", nil];NSString *str= [arry objectAtIndex:2];
NSLog(@"%@",str);

循环便利集合元素一

NSArray *arry=[NSArray arrayWithObjects:@"asd",@"bgh",@"cui",@"dqe", nil];
for (NSString *arr in arry)
 {
           NSLog(@"%@",arr);
}

NSArray的排序

        NSArray *arry=@[@"sunwukong",@"zhubajian",@"shawujing"];
        //1.选择器排序
        NSLog(@"排序前%@",arry);
        NSArray *arry1=[arry sortedArrayUsingSelector:@selector(compare:)];
        NSLog(@"排序后%@",arry1);
        //2.描述信息排序
        NSSortDescriptor *arry2=[NSSortDescriptor sortDescriptorWithKey:nil ascending:YES];
        NSArray *arry3=[arry sortedArrayUsingDescriptors:@[arry2]];
        NSLog(@"%@",arry3);
        //3.代码块排序
        NSArray *arr=[arry sortedArrayUsingComparator:^NSComparisonResult(id obj1,id obj2)
                      {
                          return [obj1 compare:obj2];
                      }];
        NSLog(@"%@",arr);

 

可变集合NSMutableArray

          初始化可变集合
        NSMutableArray *arr=[NSMutableArray arrayWithCapacity:0];
        //添加元素
        [arr addObject:@"asdf"];
        [arr addObject:@"asdfg"];
        [arr addObject:@"zxbn"];
        //在指定位置添加元素，原有的元素会向下移
        [arr insertObject:@"qwerty" atIndex:1];
        for (NSString *str in arr) {
            NSLog(@"%@",str);
        }

        NSMutableArray *arr=[NSMutableArray arrayWithCapacity:0];
        NSArray *arr1=@[@"asd",@"qwe",@"zxc"];
        //将集合的元素赋值到可变集合中
        [arr1 arrayByAddingObject:arr];
        for (NSString *arr2 in arr1) {
            NSLog(@"%@",arr2);
        }
        //将集合元素拼接成字符串
        NSString *str=[arr1 componentsJoinedByString:@"+"];
        NSLog(@"%@",str);
        //将字符串拆分
        NSArray *str1=[str componentsSeparatedByString:@"+"];
        NSLog(@"%@",str1);
        //清空集合
        [arr removeAllObjects];
        NSLog(@"%@",arr);

字典NSDictionary

        //字典的初始化
        NSDictionary *dic=[NSDictionary dictionaryWithObjectsAndKeys:@"lisi",@"name",@"guiyang",@"addr", nil];
        //元素个数
        NSLog(@"%ld",dic.count);
        //通过关键字获取value值
        NSLog(@"%@",[dic objectForKey:@"name"]);
        NSLog(@"%@",[dic objectForKey:@"addr"]);
        //所有的关键字
        NSLog(@"%@",dic.allKeys);
        //所有的value
        NSLog(@"%@",dic.allValues);
        //循环输出字典
        for (NSString *key in dic) {
            NSLog(@"%@->%@",key,[dic objectForKey:key]);
        }

NSMutableDictionary

        NSMutableDictionary *dic1=[NSMutableDictionary dictionary];
        [dic1 setObject:@"lisi" forKey:@"name"];
        [dic1 setObject:@"guiyang" forKey:@"addr"];
        
        NSMutableDictionary *dic2=[NSMutableDictionary dictionary];
        [dic2 setObject:@"wangwu" forKey:@"name"];
        [dic2 setObject:@"zunyi" forKey:@"addr"];
        //把两个可变字典组合起来
        NSArray *arry=@[dic1,dic2];
        
        for (NSDictionary *dic in arry) {
            NSLog(@"%@",[dic objectForKey:@"name"]);
            NSLog(@"%@",[dic objectForKey:@"addr"]);
        }

集NSSet

        //集 的初始化
        NSSet *set=[NSSet setWithObjects:@"asd",@"zxc",@"qwe", nil];
        //元素个数
        NSLog(@"%ld",set.count);
        NSLog(@"%@",set);
        //获取set中的元素
        NSArray *arry=[set allObjects];
        NSLog(@"%@",arry);
        //获取set中的第一个元素
        NSString *str=[set anyObject];
        NSLog(@"%@",str);
        //判断set中是否包含xxx元素
        BOOL bol=[set containsObject:@"zxc"];
        NSLog(@"%d",bol);
        
        NSSet *set1=[NSSet setWithObjects:@"hjl",@"zxc",@"qwe", nil];
        BOOL bol1=[set isEqualToSet:set1];     //判断两集是否相等
        BOOL bol2=[set isSubsetOfSet:set1];   //判断子集
        bool bol3=[set intersectsSet:set1];  //判断交集
        NSLog(@"%d",bol1);
        NSLog(@"%d",bol2);
        NSLog(@"%d",bol3);

NSMutableSet

NSMutableSet *set=[NSMutableSet set];
        [set addObject:@"zhangsan"];
        [set addObject:@"lisi"];
        [set addObject:@"wangwu"];
        //求交，并，补集
        NSMutableSet *set1=[NSMutableSet set];
        [set1 addObject:@"xiaoming"];
        [set1 addObject:@"lisi"];
        [set1 addObject:@"wangwu"];
        [set1 addObjectsFromArray:@[@"xiaoming1",@"lisi2",@"wangwu3"]];
        //交集
        [set intersectsSet:set1];
        NSLog(@"%@",set);
        //补集
        [set minusSet:set1];
        NSLog(@"%@",set);
        //并集
        [set unionSet:set1];
        NSLog(@"%@",set);