On Mon, Oct 31, 2011 at 1:14 PM, Marc Tompkins <marc.tompk...@gmail.com>wrote:
>
> You could simplify it even further by actually using the "while":
>
> > def UserChoice (): # The function that returns the choice from the
> user
> > choice = ''
> > attempt = 0
> > while choice.lower() not in ('p', 'r','s'):
> > if attempt > 0: print 'Please try again.'
> > print 'Please select (P) for paper, (R) for Rock, or (S) for
> Scissors.'
> > choice = raw_input('What is your selection?: ')
> > attempt +=1
> > return choice.lower()
>
> It's a matter of personal preference, but I try to avoid "while 1" or
> "while True" loops if at all possible. For one thing, it seems
> counter-productive to set up a loop that doesn't exit, and then to
> have to use 'break' to get out of it!
>
As a slight aside, I came up with a (fairly) simple recipe for this sort of
occasion:
def prompt(choices):
try:
for choice, desc in choices:
print("%2s. %s" % (choice, desc))
prompt.choice = input("Choice: ") #use raw_input in Python 2.x
print()
return prompt.choice
except TypeError:
raise ValueError("prompt expects collection of pairs")
Then you can do something like this:
while prompt([("P", "Paper"), ("R", "Rock"), ("S", "Scissors)]).lower() not
in ('p', 'r', 's'):
print("Error: ", prompt.choice, " is not a valid choice!")
#do something with prompt.choice here
It handles keeping track of whatever the last choice was for you, and all
you have to do is pass it a collection of pairs. If you wanted to make it
specifically for your application, you could just change it to this:
def prompt():
print("(P)aper")
print("(R)ock")
print("or (S)cissors?")
prompt.choice = raw_input("Choice: ")
return prompt.choice
while prompt().lower() not in ('p', 'r', 's'):
#print error message
HTH,
Wayne
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