Using map can do operations of current element in list:

l = [1,2,3,4,5,6];


print(list(map(lambda x: x*2, l)))  
# gives [2, 4, 6, 8, 10, 12]

In above, multiply by 2 is done for all elements in l. But how to mulitiply by 2 an element in l, only if previous value in l is odd? Can use map for this?

For example to get:

[1,4,3,8,5,12] % only 2, 4 and 6 from l are multiplyied by 2, because before them there are odd numbers 1,3,5.