How would I extract the indices of the repeated values in a list?
Do you mean a specific repeating value, or any value that occurs more than one time? Would be helpful if you post a file with your list and a little more specifics about the task.
With few lines of C# code can be done easily
Indexes_of_Duplcate_Values_v01.gh (11.0 KB)
I guess the “set” functions can help you. something different to list.