Decimal or numeric values in regular expression validation

by

A digit in the range 1-9 followed by zero or more other digits:

^[1-9]\d*$

To allow numbers with an optional decimal point followed by digits. A digit in the range 1-9 followed by zero or more other digits then optionally followed by a decimal point followed by at least 1 digit:

^[1-9]\d*(\.\d+)?$

Notes:

  • The ^ and $ anchor to the start and end basically saying that the whole string must match the pattern

  • ()? matches 0 or 1 of the whole thing between the brackets

Update to handle commas:

In regular expressions . has a special meaning – match any single character. To match literally a . in a string you need to escape the . using \. This is the meaning of the \. in the regexp above. So if you want to use comma instead the pattern is simply:

^[1-9]\d*(,\d+)?$

Further update to handle commas and full stops

If you want to allow a . between groups of digits and a , between the integral and the fractional parts then try:

^[1-9]\d{0,2}(\.\d{3})*(,\d+)?$

i.e. this is a digit in the range 1-9 followed by up to 2 other digits then zero or more groups of a full stop followed by 3 digits then optionally your comma and digits as before.

If you want to allow a . anywhere between the digits then try:

^[1-9][\.\d]*(,\d+)?$

i.e. a digit 1-9 followed by zero or more digits or full stops optionally followed by a comma and one or more digits.

More Related Contents:

  1. How can I validate an email address using a regular expression?
  2. Reference – Password Validation
  3. RegEx for matching UK Postcodes
  4. Validating IPv4 addresses with regexp
  5. Regular expression for first and last name
  6. Validating email addresses using jQuery and regex
  7. What is a regular expression which will match a valid domain name without a subdomain?
  8. Is regular expression recognition of an email address hard?
  9. How to validate phone numbers using regex
  10. Regex match one of two words
  11. Regular Expression Match to test for a valid year
  12. HTML5 input pattern search for quote
  13. US Phone Number Verification
  14. Regular expression for GB based and only numeric phone number
  15. Regex for Mobile Number Validation
  16. Regex validation of email addresses according to RFC5321/RFC5322
  17. Regex for a valid 32-bit signed integer
  18. A Regex that will never be matched by anything
  19. Redirect to other domain but keep typed domain
  20. Is it possible to increment numbers using regex substitution?
  21. C++0x regex in GCC
  22. MongoDB, performance of query by regular expression on indexed fields
  23. Make regular expression case insensitive in ASP.NET RegularExpressionValidator
  24. Find numbers after specific text in a string with RegEx
  25. Email validation using regular expression in JSF 2 / PrimeFaces
  26. Regex get domain name from email
  27. Using sed and grep/egrep to search and replace
  28. Remove square brackets from a string vector
  29. Regular Expression – How to find a match within a match?
  30. RegEx for allowing alphanumeric at the starting and hyphen thereafter

Leave a Comment