icarus a écrit :
> Hi all, i'm new to python. Learning on my own how to ask a user to
> finish a loop or not.
> For some reason, it behaves as infinite loop although I changed its
> condition. Please tell me what I'm doing wrong. Thanks in advance.
Problem mostly solved, so I'll just comment a bit on the code:
>
> condition = True
>
> while ( condition ):
You don't need the parens here
while condition:
> try:
> integer_one = int ( raw_input( "Please enter an
> integer: " ) )
> integer_two = int ( raw_input( "Please enter the
> second integer: " ) )
> division = integer_one / integer_two
>
> except( ZeroDivisionError ):
You don't need (nor want) the parens here:
except ZeroDivisionError:
> print "\nDivision by zero detected"
> except( ValueError ):
idem.
Also, the user will have to start over (ie: re enter 2 integers) if it
fails the second time.
> print "\nYou didn't enter an integer"
> else:
> print "The result is", division
> answer = raw_input("Do you want to try again (yes or
> no)? ")
> if answer == 'yes':
> condition
This line is basically a noop. You don't need this part of the branch.
> elif answer == 'no':
> condition = False
This could be rewritten as:
if answer == 'no':
condition = False
which is a very verbose way to say:
condition = (answer != 'no')
> print "Good bye, you don't want to continue"
here's a possible rewrite:
class DecodeError(RuntimeError):
pass
def nodecode(val):
return val
def decodeint(val):
try:
return int(val)
except ValueError:
raise DecodeError("%s is not an integer" % val)
YESNO={'yes':True,'y':True,'no':False,'n':False}
def decodeyesno(val):
try:
return YESNO[val.strip().lower()]
except KeyError:
raise DecodeError("please answer 'yes' or 'no'")
def read_input(prompt, decode=nodecode):
while True:
val = raw_input(prompt)
try:
return decode(val)
except DecodeError, e:
print e
def main():
run = True
while run:
integer_one = read_input("Please enter an integer: ", decodeint)
integer_two = read_input(
"Please enter the second integer: ",
decodeint
)
try:
division = integer_one / integer_two
except ZeroDivisionError:
print "Division by zero detected"
else:
print "The result is", division
run = read_input(
"Do you want to try again (yes or no)? ",
decodeyesno
)
print "Good bye, you don't want to continue"
if __name__ == '__main__':
main()
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