The best solution is to use str.join(), using ', ' as the joining string.

print(', '.join(flavours) + '.')

The best solution is to use str.join(), using ', ' as the joining string.

def display(flavours):
    print(', '.join(flavours) + '.')

Outputting:

>>> display(['chocolate', 'vanilla', 'caramel', 'strawberry', 'coffee'])
chocolate, vanilla, caramel, strawberry, coffee.

Comparing this to the two adaptions of my approach, and against AJNeufeld in one of the graphs:

NOTE: Code to plot the graphs, complete changes.