iOS 数组和字典排序

一、数组排序

  数组排序方式1：

//初始化可变数组
        NSMutableArray *arr1=[NSMutableArray arrayWithObjects:@"giu",@"min",@"Deng",@"liumin", nil];
        //字符串排序
        //创建排序描述符对象NSSortDescriptor，key为空，ascending：升序
        NSSortDescriptor *decri =[NSSortDescriptor sortDescriptorWithKey:nil ascending:YES];
        //定义一个数组，用来盛放排序条件
        NSArray *des =[NSArray arrayWithObject:decri];
        //开始排序
        [arr1 sortUsingDescriptors:des];
        //打印排序内容
        for (int i=0; i<arr1.count; i++)
        {
            NSLog(@"arr=%@",[arr1 objectAtIndex:i]);
        }

 数组排序方式2：

   NSMutableArray *arr2=[NSMutableArray arrayWithObjects:@"c", @"A",@"z",@"D",nil];
        
        //区分大小写排序 自带compar方法  选择排序
        [arr2 sortUsingSelector:@selector(compare:)];
        for (int i=0; i<arr2.count; i++)
        {
            NSLog(@"arr2=%@",[arr2 objectAtIndex:i]);
        }

二、字典的排序 

//创建5个排序对象
    NSDictionary *dic1 =@{@"price":@"30",@"name":@"liu"};
    NSDictionary *dic2 =@{@"price":@"150",@"name":@"huang"};
    NSDictionary *dic3 =@{@"price":@"37",@"name":@"yoyu"};
    NSDictionary *dic4 =@{@"price":@"25",@"name":@"yofu"};
    NSDictionary *dic5 =@{@"price":@"172",@"name":@"yosu"};
    //将这些对象放进数组
    NSArray *arr =[NSArray arrayWithObjects:dic1,dic2,dic3,dic4, dic5,nil];
    //调用数组排序方法
    NSArray *arr2 = [arr sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2)
    {
        //取出对象里的一个值作比较，根据大小返回结果
        NSString  *c = [obj1 valueForKey:@"price"];
        NSString  *d = [obj2 valueForKey:@"price"];
        int a =[c intValue]; //转成整形int比较
        int b =[d intValue];
        //按照降序排列，如果升序就返回结果对换
        if (a > b)
        {
            return NSOrderedAscending;
        }else
        {
            return NSOrderedDescending;
        }
       
    }];
    //循环遍历排序后的字典数组
    for (NSDictionary *dic in arr2)
    {
         NSLog(@"%@",dic);
    }