Pipes is really good at handling feeds, not so much with advanced string operations. However, we can be smart and do it anyway :)
for example look at this pipe. I've pre-written a list of numbers, from 0 up to 99.
Then, I use user inputs to cut that list to the relevant numbers, and tokenize that sub-list to get a feed with each number being the sole content of each item. From that feed, I build the urls.
thank you very much for your pipe.
Even if i don't really understand what's happening there i can use this - also i'm cutting down that Simple Math stuff and directly put the values (-3, 33) into Sub String.
could you post your pipe's link? I thought you were asking for an automated url building thing because of variable input. If it is not the case, you should not use the previous solution as it's an overkill and it slows down the pipe...