I’m using regular expressions to validate input and want the user to enter either “part1”, “part2”, or “part1, part2”. I tried ^(part1|part2)$, but it only works for one or the other. Is there a way to use a regex OR condition that allows matching “part1”, “part2”, or both together in any order?
I’ve dealt with this kind of pattern before. If you want to match either “part1”, “part2”, or both (like “part1, part2” or “part2, part1”), a simple alternation like ^(part1|part2)$ won’t cut it since that only allows one or the other, not both.
One way that’s worked well for me is this pattern:
^(part1, part2|part2, part1|part1|part2)$
It’s a bit brute-force, but if you’ve got just two parts, it’s manageable and clear. You just explicitly list the valid combinations. If you’re not dealing with more than a couple of parts, it’s a solid approach.
Been there! When I needed to validate flexible input like this, I realized that regex is fine for basic matching but can get ugly when combinations grow. For just “part1”, “part2”, or both with a comma and optional space, try:
^(part1(, ?part2)?|part2(, ?part1)?)$
This lets either part appear first, optionally followed by the other, with or without a space after the comma. It saved me when I had to support flexible but limited input in a form field.
I had the same problem in a validation script! If the order doesn’t matter and you only allow those specific parts, try:
^(part1|part2|part1, ?part2|part2, ?part1)$
I know it’s a little verbose, but it’s super readable and very reliable. In my case, I even put the valid options in a list and built the regex dynamically to keep it flexible. It’s cleaner than trying to get too clever with optional groups and quantifiers.