Python: How to determine how much same elements in a list are after each other?

Question

For our lecture, we need to create a program. Now we are at a point where we need help.

Let´s assume we have this following list:

[['W'], ['B'], ['B'], ['W'], ['B'], ['B'], ['B']]

Now, every letter ('W', 'B') has a specific value Just when there are two letters after each other, a player will get the points. Example:

In the list above, player 'W' would not get any point, but Player 'B' would get 5 points. 2 Points since the second element and the third element are after each other, and 3 points since the fifth, the sixth and the seventh element are after each other.

I hope it is clear what i am talking about :)

So, how do i determine, how much elements after each other are of the same value?

Thank you very much!

Answer 1

You can use itertools.groupby to iterate "groups" of equal elements in a list. Just determine the length of those groups and increase the scores accordingly:

lst = ['W', 'B', 'B', 'W', 'B', 'B', 'B']
scores = {c: 0 for c in set(lst)}
for k, g in itertools.groupby(lst):
    n = len(list(g))
    if n > 1:
        scores[k] += n

(Note: The solution is intentionally incomplete and using a slightly different input.)

Update: Assignment seems to be over; added full code.