Regex to include one thing but exclude another

Question

I've been having a lot of trouble finding how to write a regex to include certain URLs starting with a specified phrase while excluding another.

We want to include pages that start with:

/womens
/mens
/kids-clothing/boys
/kids-clothing/girls
/homeware

But we want to exclude anything that has /sXXXXXXX in the URL - where the X's are numbers.

I've written this so far to match the below URLs but it's behaving very oddly. Should I be using lookarounds or something?

\/(womens|mens|kids\-clothing\/boys|kids\-clothing\/boys|homeware).*[^s[0-9]+].*

/homeware/bathroom/s2522424/4-tier-pastel-pop-drawers-approx-91cm-x25cm-x-28cm
/homeware/bathroom/towels-and-bathmats
/homeware/bathroom/towels-and-bathmats/s2506420/boutique-luxury-towels
/homeware/bathroom/towels-and-bathmats?page=3&size=36&cols=4&sort=&id=/homeware/bathroom/towels-and-bathmats&priceRange[min]=1&priceRange[max]=14
/homeware/bathroom?page=3&size=36&cols=4&sort=&id=/homeware/bathroom&priceRange[min]=1&priceRange[max]=35
/homeware/bedroom
/homeware/bedroom/bedding-sets
/homeware/bedroom/bedding-sets/s2471012/striped-reversible-printed-duvet-set
/homeware/bedroom/bedding-sets/s2472706/check-printed-reversible-duvet-set
/homeware/bedroom/bedding-sets/s2475332/union-jack-duvet-set
/kids-clothing/boys/shop-by-age/toddler-3mnths-5yrs/s2520246/boys-lollipop-slogan-t-shirt
/kids-clothing/boys/shop-by-age/toddler-3mnths-5yrs/s2520253/boys-2-pack-dinosaur-t-shirts
/kids-clothing/girls/great-value/sale?page=1&size=36&cols=4&sort=price.asc&id=/kids-clothing/girls/great-value/sale&priceRange[min]=0.5&priceRange[max]=7
/kids-clothing/girls/mini-shops/ballet-outfits
/kids-clothing/girls/shop-by-age/baby--newborn-0-18mths
/kids-clothing/girls/shop-by-age/baby--newborn-0-18mths/s2484120/3-pack-frill-pants-pinks
/kids-clothing/girls/shop-by-age/baby--newborn-0-18mths/s2504431/3-pack-l-s-bodysuit
/mens/categories/tops?page=5&size=36&cols=4&sort=&id=/mens/categories/tops&priceRange[min]=2&priceRange[max]=22.5
/mens/categories/trousers-and-chinos
/mens/categories/trousers-and-chinos/s2438566/easy-essential-cuffed-jogging-bottoms
/mens/categories/trousers-and-chinos/s2438574/easy-essential-cuffed-jogging-bottoms
/mens/categories/trousers-and-chinos/s2458939/regatta-zip-off-lightweight-outdoor-trousers

Answer 1

You are on the right track. A negative lookahead will do it:

"^(?!.*\/s\d+)\/(womens|mens|kids\-clothing\/boys|kids\-clothing\/girls|homeware)\/.*"

The ^ anchors to the start of the string. The (?!.*\/s\d+) means that "/sXXXXXXX" can't appear anywhere in the string, and the rest of it matches your required starting tokens.

The reason [^s[0-9]+] didn't work is that [^xyz] matches only one single character. What you're effectively saying there is that you're looking for any character that isn't any combination of "s", "[" and "0-9", followed by "]". e.g. "s[234[s]".

The reason you need to put your negative lookahead at the start of the string is so nothing is matched at all. If you put it after the \/(womens|mens|kids\-clothing\/boys|kids\-clothing\/girls|homeware)\/.*, you would still successfully match everything before the "/sXXXXXXX". i.e. for line 1 of your data, you would match "/homeware/bathroom/".

Answer 2

Yes, you need a negative lookaround:

/^\/(womens|mens|kids\-clothing\/boys|kids\-clothing\/boys|homeware)(?:\/(?:(?!s\d+).)*)+$/gm

If you're comparing one line at a time you don't need the multiline (m) flag. It's probably behaving strangely because you had a character class (denoted by square brakcets) nested inside more square brackets, which doesn't work; you can't nest character classes. This was tested and works on refiddle.