在Objective-C中舍入数字 [英] Rounding numbers in Objective-C

问题描述

我想做一些数字舍入和转换为字符串以增强在Objective-C程序的输出。

我有一个float值，我想舍入到最接近的.5，然后使用它来设置标签上的文本。

例如：

1.4是一个字符串：

1.2是一个字符串：1

我花了一些时间虽然在谷歌寻找答案，但作为一个noob与Objective-C，我不知道要搜索什么！

谢谢，
Ash

解决方案

感谢大家的指示，我设法想出了一个解决方案：

  float roundedValue = round（2.0f * number）/ 2.0f; 
 NSNumberFormatter * formatter = [[NSNumberFormatter alloc] init]; 
 [formatter setMaximumFractionDigits：1]; 
 [formatter setRoundingMode：NSNumberFormatterRoundDown]; 
 
 NSString * numberString = [formatter stringFromNumber：[NSNumber numberWithFloat：roundedValue]]; 
 [formatter release]; 
  

上面的测试用例适用于我的测试用例，但如果有人知道更好的方法这我有兴趣听到！

I'm trying to do some number rounding and conversion to a string to enhance the output in an Objective-C program.

I have a float value that I'd like to round to the nearest .5 and then use it to set the text on a label.

For example:

1.4 would be a string of: 1.5

1.2 would be a string of: 1

0.2 would be a string of: 0

I've spent a while looking on Google for an answer but, being a noob with Objective-C, I'm not sure what to search for! So, I'd really appreciate a pointer in the right direction!

Thanks, Ash

解决方案

Thanks for the pointers everyone, I've managed to come up with a solution:

float roundedValue = round(2.0f * number) / 2.0f;
NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
[formatter setMaximumFractionDigits:1];
[formatter setRoundingMode: NSNumberFormatterRoundDown];

NSString *numberString = [formatter stringFromNumber:[NSNumber numberWithFloat:roundedValue]];
[formatter release];

The above works for the test cases I threw at it, but if anyone knows a better way to do this I'd be interested to hear it!

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