如何计算iOS中的浮点数后的位数？ [英] How to calculate number of digits after floating point in iOS?

问题描述

例如：

如何计算iOS中浮点数的位数？ >

• 3.105应该返回3


• 3.0应该返回0


• 2.2应该返回1
  

更新：
我们还需要添加以下示例。因为我想知道小数部分的位数。

• 1e-1应该返回1




解决方案

我使用的是以下内容：



  NSString * priorityString = [[NSNumber numberWithFloat：self.priority] stringValue]; 
 NSRange range = [priorityString rangeOfString：@。]; 
 int数字; 
 if（range.location！= NSNotFound）{
 priorityString = [priorityString substringFromIndex：range.location + 1]; 
 digits = [priorityString length]; 
} else {
 range = [priorityString rangeOfString：@e-]; 
 if（range.location！= NSNotFound）{
 priorityString = [priorityString substringFromIndex：range.location + 2]; 
 digits = [priorityString intValue]; 
} else {
 digits = 0; 
} 
} 
  




How can I calculate the number of digits after the floating point in iOS?

For example:

• 3.105 should return 3
• 3.0 should return 0
• 2.2 should return 1

Update: Also we need to add the following example. As I want to know number of digits in the fraction part.

• 1e-1 should return 1

解决方案

What I used is the following:

NSString *priorityString = [[NSNumber numberWithFloat:self.priority] stringValue];
    NSRange range = [priorityString rangeOfString:@"."];
    int digits;
    if (range.location != NSNotFound) {
        priorityString = [priorityString substringFromIndex:range.location + 1];
        digits = [priorityString length];
    } else {
        range = [priorityString rangeOfString:@"e-"];
        if (range.location != NSNotFound) {
            priorityString = [priorityString substringFromIndex:range.location + 2];
            digits = [priorityString intValue];
        } else {
            digits = 0;
        }
    }

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