如何为用例构造正则表达式？

Question

I am looking for a regular expression for the following requirement. Can somebody help with this?

1. Only decimals, -/+ and . (dot) are Allowed.
2. Max length is 9 (including .(dot) and -/+ (minus)).

Examples:

123456789
-12345678
.12345678
-.1234567
-.123
123.45
-123.450
+23.34
_34.

Answer 1

Try this: ^[\\d+-.]{1,9}$

[\\d+-.] - digits, +, - and . (dot).
{1,9} - max length is 9, min is 1 (but you can change it).

Here you can find how it works.