Changing elements of a list to match another list

[perfringo]

If I correctly understand the objective then no iteration is needed.

You just want to replace first element in every row in matrix with value which in reference list. As indexes of rows in matrixes and elements in reference list are the same one can just:

>>> lst = [[2,13,22,40],[8,13,22,40],[24,13,22,40]]                  
>>> reference = [5, 10, 30]                                          
>>> for i, v in enumerate(reference): 
...     lst[i][0] = v 
...
>>> lst                                                              
[[5, 13, 22, 40], [10, 13, 22, 40], [30, 13, 22, 40]]