Hi,
I need some help writing a formula that will concatenate columns by rows but
where the number of columns to be concatenated differs between the rows. I
also need to place comma delimiters between each value.

For Example
Row1: 345 3432 5631 76523 342
Row2: 87 234 546

My results need to show:
Row1: 345,3432,5631,76523,342
Row2: 87,234,546

This sounds easy, but I need Row2 to avoid showing the last two commas:
87,234,546,,

Thanks for the help!