Adding an index to a list of a lists in python

Question

I have a list of lists like this:-

x=[['A','B','C','D'],['E','F','G','H']]

I am trying to add an index to the list like this:-

y=[[0,'A','B','C','D'],[1,'E','F','G','H']]

Is there any way to achieve this?

Answer 1

y = [[i]+a for i,a in enumerate(x)]