[英]Compare two strings meaningfully in Java
I've two strings which I need to compare, but I want to compare them meaningfully such that when they are numbers their actual value should be compared. 我有两个字符串需要比较,但我想有意义地比较它们,当它们是数字时,它们的实际值应该进行比较。 So far I've tried the following solution:
到目前为止,我尝试了以下解决方案:
String str1 = "-0.6";
String str2 = "-.6";
if (NumberUtils.isNumber(str1) && NumberUtils.isNumber(str2)) {
Number num1 = NumberUtils.createNumber(str1);
Number num2 = NumberUtils.createNumber(str2);
System.out.println(num1.equals(num2));
} else {
System.out.println(str1.equals(str2));
}
This works as both are converted to double
s. 这适用于两者都转换为
double
s。
But this won't work in this case where: 但是在这种情况下这不起作用:
String str1 = "6";
String str2 = "6.0";
Is there any easy way to do this, or will I have to write my own Comparator? 有没有简单的方法可以做到这一点,还是我必须编写自己的比较器?
Instead of using the general-purpose createNumber(String)
, force them to double
s using createDouble(String)
: 而不是使用通用的
createNumber(String)
,使用createDouble(String)
强制它们double
:
String str1 = "-0.6";
String str2 = "-.6";
if (NumberUtils.isNumber(str1) && NumberUtils.isNumber(str2)) {
Double d1 = NumberUtils.createDouble(str1);
Double d2 = NumberUtils.createDouble(str2);
System.out.println(d1.equals(d2));
} else {
System.out.println(str1.equals(str2));
}
You can probably use BigDecimal
for this: 您可以使用
BigDecimal
:
final BigDecimal b1 = new BigDecimal(str1);
final BigDecimal b2 = new BigDecimal(str2);
return b1.compareTo(b2) == 0;
You could use Double.parseDouble(String)
instead. 您可以使用
Double.parseDouble(String)
。 It throws the NumberFormatException
, which can be caught to inform you that you should not compare them as numbers. 它会抛出
NumberFormatException
,可以捕获它以通知您不应将它们作为数字进行比较。
try {
Double d1 = Double.parseDouble(str1);
Double d2 = Double.parseDouble(str2);
//Now you have your doubles
} catch (NumberFormatException e)
{
//Could not compare as numbers, do something else
}
As suggested on the comment one of the string could be a number
and the other not or vice versa or both could be a string
so instead of checking if the strings are number strings I will go using try catch
block. 正如评论中所建议的那样,字符串中的一个可以是
number
而另一个不是,反之亦然,或者两者都可以是string
所以不是检查字符串是否是数字字符串,而是使用try catch
块。
Like this: 像这样:
try{
Double d1 = Double.parseDouble(str1);
Double d2 = Double.parseDouble(str2);
System.out.println(d1.equals(d2));
}catch(NumberFormatException ex){
System.out.println(num1.equals(num2));
}
This first tries to compare them as numbers but if at least one of them is not a number string it will fallback to string comparison in the catch
block. 这首先尝试将它们作为数字进行比较,但如果它们中的至少一个不是数字字符串,它将回退到
catch
块中的字符串比较。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.