I was wondering how would you can replace values of a list using list comprehension. e.g.

theList = [[1,2,3],[4,5,6],[7,8,9]]
newList = [[1,2,3],[4,5,6],[7,8,9]]
for i in range(len(theList)):for j in range(len(theList)):if theList[i][j] % 2 == 0:newList[i][j] = 'hey'

I want to know how I could convert this into the list comprehension format.

You can just do a nested list comprehension:

theList = [[1,2,3],[4,5,6],[7,8,9]]
[[x if x % 2 else 'hey' for x in sl] for sl in theList]

returns

[[1, 'hey', 3], ['hey', 5, 'hey'], [7, 'hey', 9]]