3

我正在通过网络服务列出一个项目的数量百分比，例如一个项目。我得到的响应是一个类似于下面代码的字典数组。我需要它以排序格式

NSArray *numberArray = [NSArray arrayWithObjects:
    [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithFloat:-12.0], @"price", nil],
    [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithFloat:-86.0],@"price", nil],
    [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithFloat:-8.0],@"price", nil],
    [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithFloat:12.0],@"price", nil],
    [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithFloat:2.0],@"price", nil],
    [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithFloat:112.0],@"price", nil], nil];

这是 JSON 响应的日志

[
    {
        price = "-12";
    },
        {
        price = "-86";
    },
        {
        price = "-8";
    },
        {
        price = 12;
    },
        {
        price = 2;
    },
        {
        price = 112;
    }
]
4

4 回答 4

4 
NSArray *sortedResult = [numberArray sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
    NSNumber *num1 = [obj1 objectForKey:@"price"];
    NSNumber *num2 = [obj2 objectForKey:@"price"];
    return [num1 compare:num2];
}];
NSLog(@"---%@",sortedResult);

如果您希望 sortedResult 按降序排列，则在
return 语句中交换 num1 和 num2。

于 2013-08-29T12:05:42.857 回答
2

如果价格存储为NSNumber对象，那么来自@trojanfoe 链接的方法（Best way to sort an NSArray of NSDictionary objects?）应该可以工作：

NSSortDescriptor *sd = [NSSortDescriptor sortDescriptorWithKey:@"price" ascending:YES];
NSArray *sorted = [numberArray sortedArrayUsingDescriptors:@[sd]];

但从您的最后评论看来，价格存储为字符串。在这种情况下，以下方法有效，因为floatValue将每个字符串转换为浮点值：

NSSortDescriptor *sd = [NSSortDescriptor sortDescriptorWithKey:@"price.floatValue" ascending:YES];
NSArray *sorted = [numberArray sortedArrayUsingDescriptors:@[sd]];
于 2013-08-29T12:04:45.480 回答
1

您没有对数字进行排序。您正在根据常见的“价格”元素对字典进行排序：

sortedArray = [numberArray sortedArrayUsingComparator:^NSComparisonResult(NSDictionary *a, NSDictionary *b) {
    return [a[@"price"] compare:b[@"price"]];
}];
于 2013-08-29T12:18:04.803 回答
0 
sortedArray = [numberArray sortedArrayUsingComparator:^NSComparisonResult(id a, id b) {
    float first  = [(NSNumber *)a[@"price"] floatValue];
    float second = [(NSNumber *)b[@"price"] floatValue];

    if (first > second) {
        return NSOrderedDescending;
    } else if (first < second) {
        return NSOrderedAscending;
    }

    return NSOrderedSame;
}];
于 2013-08-29T12:00:12.137 回答