I want a java regex expression that accepts only the numbers and dots.
for example,
1.1.1 ----valid 1.1 ----valid 1.1.1.1---valid 1. ----not valid The dots should not be at the starting position or at the ending position.
05 Answers
I guess this is what you want:
^\d+(\.\d+)*$ Explanation: It accepts numbers separated by dots; it starts and ends with number; a number can have multiple digits; one number without dots is also accepted.
Variant without multiple digits:
^\d(\.\d)*$ Variants where at least one dot is required:
^\d+(\.\d+)+$ ^\d(\.\d)+$ Don't forget that in Java you have to escape the \ symbols, so the code will look like this:
Pattern NUMBERS_WITH_DOTS = Pattern.compile("^\\d+(\\.\\d+)*$"); So you want a regex that wants numbers and periods but starts and ends with a number?
"[0-9][0-9.]*[0-9]" But this isn't going to match things like 1. which doesn't have any periods, but does start and end with a number.
I guess this is what you want:
Pattern.compile("(([0-9](\\.[0-9]*))?){1,13}(\\.[0-9]*)?(\\.[0-9]*)?(\\.[0-9]*)?", Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE | Pattern.DOTALL | Pattern.MULTILINE); Explanation: It accepts numbers separated by dots; it starts and ends with number; a number can have multiple digits; one number without dots is not accepted.
The output like this--
- 1.1
- 1.12
- 1.1.5
- 1.15.1.4
<!DOCTYPE html> <html> <body> <p>RegEx to allow digits and dot</p> Number: <input type="text" onkeyup="myFunction()"> <script> function myFunction() { var x = document.getElementById("fname"); x.value = x.value.replace(/[^0-9\.]/g,""); } </script> </body> </html> "^\\d(\\.\\d)*$" 1 ----valid (if it must be not valid, replace `*` => `+` ) 1.1.1 ----valid 1.1 ----valid 1.1.1.1---valid 1. ----not valid 11.1.1 ---not valid (if it must be valid, add `+` after each `d`) 
