How do I find the last six digits of a string using regex in java?
For instance, I have a string: 238428342938492834823
I want to have string that finds only the last 6 digits, no matter what the length of the string is. I have tried "/d{6}$"
with no success.
Any suggestions or new ideas?
You just used the wrong escape character. \\d{6}
matches six digits, while /d
matches a literal forward-slash followed by six literal d
's.
The pattern should be:
\d{6}$
Of course, in Java, you also have to escape the \\
, so that:
String pattern = "\\d{6}$";
The other answer provides you with a regex solution to this problem, however regex is not a reasonable solution to the problem.
if (text.length >= 6) {
return text.substring(text.length - 6);
}
If you find yourself trying to use regex to solve a problem, the first thing you should do is stop and have a good think about why you think regex is a good solution.
If your String always consists out of just digits, you should consider using a different datatype.
import java.math.BigInteger;
import java.text.DecimalFormat;
import java.text.NumberFormat;
public class Numberthings {
static final BigInteger NUMBER_1000000 = BigInteger.valueOf(1000000);
static final NumberFormat SIX_DIGITS = new DecimalFormat("000000");
public static void main(String[] args) {
BigInteger number = new BigInteger("238428342938492834823");
BigInteger result = number.remainder(NUMBER_1000000);
System.out.println(SIX_DIGITS.format(result.longValue()));
number = new BigInteger("238428342938492000003");
result = number.remainder(NUMBER_1000000);
System.out.println(SIX_DIGITS.format(result.longValue()));
}
}
This results in the following output:
834823
000003
这是您如何一行完成的操作:
String last6 = str.replaceAll(".*(.{6})", "$1");
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