Re: [Tutor] Output never stops
David wrote:
[snip]
#!/usr/bin/python
person = {'Lary':43,'Joan':24}
choice = 0
while choice != '-1':
if choice == '':
print You must enter Lary or Joan to continue! (-1 to quit):
choice = raw_input(
Who's age do want to know, Lary or Joan? (-1 to quit): )
if choice == 'Lary':
print Lary's age is:, person.get('Lary')
elif choice == 'Joan':
print Joan's age is:, person.get('Joan')
else:
print Goodbye!
Consider leveraging the dictionary (and some otherPythonic
refinements). Separate the logic from the data. Now you can add more
names and ages without changing the logic.
#!/usr/bin/python
person = {'Lary':43, 'Joan':24, 'Bob':68}
keys = person.keys()
names = ', '.join(keys[:-1]) + ' or ' + keys[-1]
while True:
choice = raw_input(Who's age do want to know, %s? (-1 to quit): %
names)
age = person.get(choice, None)
if age is not None:
print choice + 's age is:, age
elif choice == -1:
print Goodbye!
break
else:
print Invalid choice + choice
--
Bob Gailer
919-636-4239 Chapel Hill, NC
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Re: [Tutor] Output never stops
David [EMAIL PROTECTED] wrote
the output never stops when I run this in a terminal
choice = raw_input(Enter the name Lary or Joan (-1 to quit): )
while choice != '-1':
person = {'Lary': 43,'Joan': 24}
if choice == 'Lary':
print Lary's age is:, person.get('Lary')
elif choice == 'Joan':
print Joan's age is:, person.get('Joan')
else:
print 'Bad Code'
You set choice outside the while loop then never change
it so the while test will always be true and loop forever.
You need to copy the raw_input line into the body of
the while loop to reset choice.
Also for good style you should move the person = {} line outside
the loop since you only want to set up the dictionary once,
not every time you execute the loop. The dictionary never
changes so recreating it every time is wasteful.
HTH,
--
Alan Gauld
Author of the Learn to Program web site
http://www.freenetpages.co.uk/hp/alan.gauld
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Re: [Tutor] Output never stops
Alan Gauld wrote:
David [EMAIL PROTECTED] wrote
the output never stops when I run this in a terminal
choice = raw_input(Enter the name Lary or Joan (-1 to quit): )
while choice != '-1': person = {'Lary': 43,'Joan': 24}
if choice == 'Lary':
print Lary's age is:, person.get('Lary')
elif choice == 'Joan':
print Joan's age is:, person.get('Joan')
else:
print 'Bad Code'
You set choice outside the while loop then never change it so the
while test will always be true and loop forever.
You need to copy the raw_input line into the body of the while loop to
reset choice.
Also for good style you should move the person = {} line outside the
loop since you only want to set up the dictionary once, not every time
you execute the loop. The dictionary never changes so recreating it
every time is wasteful.
HTH,
Thanks Alan, also your tutorial/book is a big help. I think I got it :)
#!/usr/bin/python
person = {'Lary':43,'Joan':24}
choice = 0
while choice != '-1':
if choice == '':
print You must enter Lary or Joan to continue! (-1 to quit):
choice = raw_input(
Who's age do want to know, Lary or Joan? (-1 to quit): )
if choice == 'Lary':
print Lary's age is:, person.get('Lary')
elif choice == 'Joan':
print Joan's age is:, person.get('Joan')
else:
print Goodbye!
--
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Re: [Tutor] Output never stops
David [EMAIL PROTECTED] wrote
Thanks Alan, also your tutorial/book is a big help. I think I got it
:)
Close but not quite there yet.
choice = 0
while choice != '-1':
if choice == '':
print You must enter Lary or Joan to continue! (-1 to quit):
choice = raw_input(
Who's age do want to know, Lary or Joan? (-1 to quit):
)
if choice == 'Lary':
print Lary's age is:, person.get('Lary')
elif choice == 'Joan':
print Joan's age is:, person.get('Joan')
else:
print Goodbye!
Consider what happens if I enter a blank name.
You print Goodbye but then go round the loop again prompting
for another choice. You probably want the Goodbye to only
be printed if choice == '-1'?
And the test for the empty string should ptrobably be after
you ask for the input?
Also the normal way to access a dictionary value is to
use square brackets:
person['Lary']
get() does have the advantage that you can add a default
value that is returned if the key doesn't exist. But that's
not relevant in this case.
HTH,
--
Alan Gauld
Author of the Learn to Program web site
http://www.freenetpages.co.uk/hp/alan.gauld
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[Tutor] Output never stops
Very new to python and never programed before. Can not figure out why
the output never stops when I run this in a terminal
#!/usr/bin/python
choice = raw_input(Enter the name Lary or Joan (-1 to quit): )
while choice != '-1': person = {'Lary': 43,'Joan': 24}
if choice == 'Lary':
print Lary's age is:, person.get('Lary')
elif choice == 'Joan':
print Joan's age is:, person.get('Joan')
else:
print 'Bad Code'
--
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Re: [Tutor] Output never stops
David wrote:
Very new to python and never programed before. Can not figure out why
the output never stops when I run this in a terminal
#!/usr/bin/python
choice = raw_input(Enter the name Lary or Joan (-1 to quit): )
while choice != '-1': person = {'Lary': 43,'Joan': 24}
if choice == 'Lary':
print Lary's age is:, person.get('Lary')
elif choice == 'Joan':
print Joan's age is:, person.get('Joan')
else:
print 'Bad Code'
should have been like this;
#!/usr/bin/python
choice = raw_input(Enter the name Lary or Joan (-1 to quit): )
while choice != '-1':
person = {'Lary': 43,'Joan': 24}
if choice == 'Lary':
print Lary's age is:, person.get('Lary')
elif choice == 'Joan':
print Joan's age is:, person.get('Joan')
else:
print 'Bad Code'
--
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Re: [Tutor] Output never stops
Hi David,
Simple explanation - you should use if instead of while. A while
statement executes whatever is in that block again and again until
the condition becomes false. So your code, the way you have it, first
checks if the user's input is not -1. If you have typed Lary, it goes
on to print Lary, hits the end of the while block, and starts back at
the top, since choice still is not -1. If you change while to if, the
statement will only be executed once.
Here's a scenario you might want to use a while loop (which might be
what you were trying to do): suppose you want to keep on asking for
input if the input is not a quit code, or valid input. To do this,
you could just put the choice = raw_input line inside the while
block, and perhaps make sure to initialize choice to '' (an empty
string or something).
Vivek
On Aug 2, 2008, at 10:21 PM, David wrote:
David wrote:
Very new to python and never programed before. Can not figure out
why the output never stops when I run this in a terminal
#!/usr/bin/python
choice = raw_input(Enter the name Lary or Joan (-1 to quit): )
while choice != '-1': person = {'Lary': 43,'Joan': 24}
if choice == 'Lary':
print Lary's age is:, person.get('Lary')
elif choice == 'Joan':
print Joan's age is:, person.get('Joan')
else:
print 'Bad Code'
should have been like this;
#!/usr/bin/python
choice = raw_input(Enter the name Lary or Joan (-1 to quit): )
while choice != '-1': person = {'Lary': 43,'Joan': 24}
if choice == 'Lary':
print Lary's age is:, person.get('Lary')
elif choice == 'Joan':
print Joan's age is:, person.get('Joan')
else:
print 'Bad Code'
--
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