可接受以数字输入开头的Java正则表达式

Question

I need to support inputs of int numbers like "100", double like "150.84", but also be able to accept an input like this "-458.2" or "-450".

For the int/double part I use : input.matches("\\\\d+\\\\.\\\\d+")) || input.matches("\\\\d+")) input.matches("\\\\d+\\\\.\\\\d+")) || input.matches("\\\\d+"))

But how can make it acceptable to have the minus character at the beginning?

Answer 1

You can allow an optional - like this:

 input.matches("-?\\d+\\.\\d+"))

You can also write it in one Regex:

input.matches("-?\\d+(?:\\.\\d+)?"))

?: declares a non-capturing group since you don't want to extract this part