如何避免在NSNumberFormatter中舍入 [英] How to avoid rounding off in NSNumberFormatter

问题描述

我正在尝试使用一个最大2位小数精度的数字字符串，而其余小数只是修剪掉而不是将它们四舍五入。例如：

我有：123456.9964

我想：123456.99 - >只是想修剪小数点的其余部分

我试过的是：

< pre class =lang-cs prettyprint-override> NSNumberFormatter * numberFormatter = [[NSNumberFormatter alloc] init];
[numberFormatter setNumberStyle：NSNumberFormatterDecimalStyle];
[numberFormatter setMaximumFractionDigits：2];
NSString * numberAsString = [numberFormatter stringFromNumber：[NSNumber numberWithFloat：123456.9964]];
NSLog（@％@，numberAsString）;


没有什么可以将舍入模式设置为无。我还能做些什么来保持十进制样式格式以及修剪过的十进制数字？任何帮助将不胜感激。谢谢。

解决方案

以下适用于我：

  NSNumberFormatter * numberFormatter = [[NSNumberFormatter alloc] init]; 
 [numberFormatter setNumberStyle：NSNumberFormatterDecimalStyle]; 
 [numberFormatter setMaximumFractionDigits：2]; 
 //可选 -  [numberFormatter setMinimumFractionDigits：2]; 
 [numberFormatter setRoundingMode：NSNumberFormatterRoundDown]; 
 NSNumber * num = @（123456.9964）; 
 NSString * numberAsString = [numberFormatter stringFromNumber：num]; 
 NSLog（@％@，numberAsString）; 
  

输出为：123,456.99

部分你的问题是使用 numberWithFloat：而不是 numberWithDouble：。您的号码有太多数字 float 。

I am trying to have a number string with maximum 2 decimals precision, while rest decimals just trimmed off instead of rounding them up. For example:

I have: 123456.9964

I want: 123456.99 -> Just want to trim rest of the decimal places

What I have tried is:

NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
[numberFormatter setNumberStyle: NSNumberFormatterDecimalStyle];
[numberFormatter setMaximumFractionDigits:2];
NSString *numberAsString = [numberFormatter stringFromNumber:[NSNumber numberWithFloat: 123456.9964]];
 NSLog(@"%@", numberAsString);

There is nothing to set rounding mode as "none". What else can I do to maintain Decimal style formatting along with trimmed decimal digits? Any help will be appreciated. Thanks.

解决方案

The following works for me:

NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
[numberFormatter setNumberStyle:NSNumberFormatterDecimalStyle];
[numberFormatter setMaximumFractionDigits:2];
// optional - [numberFormatter setMinimumFractionDigits:2];
[numberFormatter setRoundingMode:NSNumberFormatterRoundDown];
NSNumber *num = @(123456.9964);
NSString *numberAsString = [numberFormatter stringFromNumber:num];
NSLog(@"%@", numberAsString);

The output is: 123,456.99

Part of your problem is the use of numberWithFloat: instead of numberWithDouble:. Your number has too many digits for float.

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