Remove every second comma from string (python)

Question

I would like to remove every second occurence of a comma in my string but starting from the second comma. My string: "30, 20, 40, 50" and I would like my result to be: "30 20, 40 50" So far I have been using regular expressions to try and achieve this by the following reg sub: myString = re.sub('(,[^,])*,', r'\1', myString) but this results in: "30, 20 40, 50". I hope someone can help me out here.

Answer 1

You can group the non-comma characters and the optional following comma for preservation instead:

myString = re.sub(',([^,]*,?)', r'\1', myString)

Demo: https://replit.com/@blhsing/EminentWholeOctagons

Answer 2

Thanks to those that responded. My own solution meanwhile ended up being: myString = re.sub(',([^,]*[,]*)', r'\1', myString)