i need help with a REGEX expression (for analytics). not sure how to handle the requirements. here's an example of a URL: /a.html?ref=aa&project=11&utm=bb

this URL ould have &project=XX in the middle but it is possible that &project won't be there at all..

requirements -

1. i want the regex to be positive only for specific project=XX (for example only when XX equals 11 or 12 or 13) but negative for all other values (project=22).
2. the parameter before it (?ref in the example below) is mandatory
3. any parameter afterwards (&utm) is optional.

for example -

• fine: /a.html?ref=aa&project=11&utm=bb
• fine: /a.html?ref=aa&utm=bb
• not fine: /a.html?ref=aa&project=22&utm=bb

how do i approach this?

i tried this it kinda works (but only without additional utm params):

/a.html?ref=aa(&project=(11|12|13))?$

i tried this, but it doesn't work when using the utm paramater :

/a.html?ref=aa(&project=(11|12|13))?(&utm=.*)?$

thanks Itay

CodePudding user response：

You don't say what platform you're using, but you'll need to escape your forward slashes and question marks if you want them to match literal characters on most platforms:

\/a.html\?ref=aa(&project=(11|12|13))?(&utm=.*)?$

You might also want to minimize your capture in the utm block in case other things come after it that you don't want:

\/a.html\?ref=aa(&project=(11|12|13))?(&utm=.*?)?$

CodePudding user response：

You could use character class [123] to match either 1,2 or 3 with a single optional group, and note to escape the dot to match it literally.

\/a\.html\?ref=aa(&project=1[123])?&utm=.*$

The pattern matches:

• \/a\.html match /a.html
• \?ref=aa Match ?ref=aa
• ( Capture group
  • &project=1[123] Match &project=1 and then either 1,2 or 3
• )? Close the non capture group to make it optional
• &utm=.*$ Match &utm= followed by the rest of the line

Regex demo