如何在Java中使用正则表达式检查数字？

Question

I have given file name as

B-018 MyName

I want to check whether first four characters are in format of

'B-< Numeric >< Numeric >< Numeric >

B- will be constant for all names and i want to check if three succeeding characters are numeric.

How to do it using Regular Expressions in Java?

Answer 1

The following expression implements your requirement.

java.util.regex.Pattern.compile("B-\\d{3} .*").matcher("B-018 MyName").matches()

It checks that the expressions is "B-(3-digits) (any character zero or more time)".

I advise you to use a site as https://regex101.com/ to learn some basis about regex and test your expressions. This expression can be retrieved using this link https://regex101.com/r/B0GN8F/1 .