formatting list -> comma separated (slightly different)

[Michiel Overtoom]

Paul & Robert wrote...

> d = ["soep", "reeds", "ook"]
>print ', '.join(d)
> soep, reeds, ook

I occasionally have a need for printing lists of items too, but in the form:
"Butter, Cheese, Nuts and Bolts".  The last separator is the word 'and'
instead of the comma. The clearest I could come up with in Python is below.
I wonder if there is a more pythonic solution for this problem.  Maybe
something recursive?

Greetings,


'''
Formatting a sequence of items such that they are separated by
commas, except the last item, which is separated by the word 'and'.

Used for making lists of dates and items more human-readable
in generated emails and webpages.

For example:

Four friends have a dinner: Anne, Bob, Chris and Debbie
Three friends have a dinner: Anne, Bob and Chris
Two friends have a dinner: Anne and Bob
One friend has a dinner: Anne
No friend has a dinner:

     ['Anne','Bob','Chris','Debbie'] -> "Anne, Bob, Chris and Debbie"
     ['Bob','Chris','Debbie'] -> "Bob, Chris and Debbie"
     ['Chris','Debbie'] -> "Chris and Debbie"
     ['Debbie'] -> "Debbie"
     [] -> ""

'''

def pretty(f):
    if len(f)==0: return ''
    if len(f)==1: return f[0]
    sepwithcommas=f[:-1]
    sepwithand=f[-1]
    s=', '.join(sepwithcommas)
    if sepwithand:
        s+=' and '+sepwithand
    return s

friends=['Anne','Bob','Chris','Debbie','Eve','Fred']
while True:
    print friends,'->',pretty(friends)
    if friends:
        friends.pop(0)
    else:
        break





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