creating strings without commas not followed by a space

Hi,

I have looked almost everywhere on the forum and couldn't find a solution: I need to construct a message for a [dict] with latitude and longitude coordinates. The tricky thing is that those coordinates have to be expressed as follows:

float,float

No space between the two floats.
So far, I have used [combine] and I have managed to get:
float\,float
I had never heard of [regexp] until now. I am not sure there is a way to have those \ removed.

Another way would be using a [tosymbol], but the commas disappear. Addtionnally, [sprintf] systematically adds spaces after commas.
Precision: the message has to be structured as follows:
set url::httpblablabla/float,float

thanks to anyone who would have a better idea…