Regular expression to match digits and basic math operators

by

The accepted answer can’t handle a lot of basic cases.
This should do the job:

^([-+]? ?(\d+|\(\g<1>\))( ?[-+*\/] ?\g<1>)?)$

Explaination:

We want to match the entire string:

^...$

Expressions can have a sign:

[-+]? ?

An expression consists of multiple digits or another valid expression, surrounded by brackets:

(\d+|\(\g<1>\))

A valid expression can be followed by an operation and another valid expression and is still a valid expression:

( ?[-+*\/] ?\g<1>)?

More Related Contents:

  1. Awk – replace coumn 2 in table 1 from coumn 2 in table 2 based on matching data in column 1 (common between tables)
  2. Reference – What does this regex mean?
  3. How do I match any character across multiple lines in a regular expression?
  4. How do you match only valid roman numerals with a regular expression?
  5. Validating IPv4 addresses with regexp
  6. Regular expression pipe confusion
  7. How to use conditionals when replacing in Notepad++ via regex
  8. Find CRLF in Notepad++
  9. Jmeter extracting fields/parsing JSON response
  10. How to back reference “inner” selections ( () ) in a regular expression?
  11. Verbs that act after backtracking and failure
  12. mod_rewrite: replace underscores with dashes
  13. Multiline regex to match config block
  14. How is the AND/OR operator represented as in Regular Expressions?
  15. Remove ‘index.php’ from URL with .htaccess
  16. Regex Until But Not Including
  17. Math operations in regex
  18. Multiple words in any order using regex [duplicate]
  19. Match at every second occurrence
  20. Deprecated: Function split() is deprecated. How to rewrite this statement?
  21. PostgreSQL Regex Word Boundaries?
  22. Does bash support word boundary regular expressions?
  23. How to use awk variables in regular expressions?
  24. 301 Redirect to replace all spaces to hyphens
  25. RegEx with Excel VBA on Mac
  26. Regular expression to find two strings anywhere in input
  27. Regex validate correct ISO8601 date string with time
  28. Regular Expression – Validate Gmail addresses
  29. Regex lazy vs greedy confusion
  30. Matching url with array list of words in AngularJS ui-router

Leave a Comment