Loops (and the in operator) [solved]

[Metalhead]

Hi,
I'm new to Python and OO in general. I am trying to set up a simple loop based around an inputed answer to a question, so that if you input a wrong answer, you are asked the question again, but if correct, the program moves on.

For example:
What is the capital of France?

Correct answer - move on to next question. Wrong answer. Repeat the question

I used to write in basic years ago in which programs had line numbers and would have went something like this. It was easy to direct the program back again to ask the question again.


10 print "what is the capital of France?"
20 get a$ #user inputs answer
30 If A$ = "Paris" then goto 60
40 print "That is the wrong answer!. Try again"
50goto 10
60 The next question........

I'm really finding it hard to get my head round loops without line numbers.
thanks,
tim

[bvdet]

Hi,
I'm new to Python and OO in general. I am trying to set up a simple loop based around an inputed answer to a question, so that if you input a wrong answer, you are asked the question again, but if correct, the program moves on.

For example:
What is the capital of France?

Correct answer - move on to next question. Wrong answer. Repeat the question

I used to write in basic years ago in which programs had line numbers and would have went something like this. It was easy to direct the program back again to ask the question again.


10 print "what is the capital of France?"
20 get a$ #user inputs answer
30 If A$ = "Paris" then goto 60
40 print "That is the wrong answer!. Try again"
50goto 10
60 The next question........

I'm really finding it hard to get my head round loops without line numbers.
thanks,
tim

Try this:

z=1
while z:
    answer = ....ask for input...
    if answer in [...list of possible correct answers...]:
        break
    else:
        print "You have entered an incorrect answer. Try again."
 

[bartonc]

Read yesterday's post "need help with code structure" for pythonic structure on how to do this.

[Metalhead]

Thanks for the replies. I've solved most of the problem. Can someone tell me why this dooes not work

namestring = input("WHAT IS YOUR NAME?" )
while namestring == 'Jack':
age = 9
while namestring == 'Rachel':
age = 7

I'm trying to set a value for age depending on what name was entered.
Also, is there a way to make Python ignore upper,lower case or a command along th same lines as
while namestring = 'Jack' or 'JACK' or 'jack':
age=9

thanks

[Metalhead]

the age is indented by the way. It just did not show on the message

tim

[bartonc]

the age is indented by the way. It just did not show on the message

tim

That's because you didn't USE CODE TAGS! The background of the post screen has it, the panel on the right of the post screen has it, the sticky at the top of this forum has it. Read them. Use them. It helps us a lot.

Thanks for posting, keep it up. Use code tags. Thanks,
Barton

[bartonc]

Thanks for the replies. I've solved most of the problem. Can someone tell me why this dooes not work

namestring = input("WHAT IS YOUR NAME?" )
while namestring == 'Jack':
age = 9
while namestring == 'Rachel':
age = 7

I'm trying to set a value for age depending on what name was entered.
Also, is there a way to make Python ignore upper,lower case or a command along th same lines as
while namestring = 'Jack' or 'JACK' or 'jack':
age=9

thanks

while creates a loop which needs a condition that changes (to "no longer true") or a break statement in order to break out of the loop.

namestring = raw_input("WHAT IS YOUR NAME? " )
namestring = namestring.captalize() # use str type method to get a capitalized copy of namestring
if namestring == 'Jack':
    age = 9
if namestring == 'Rachel':
    age = 7
 

type
help(str)
to see all the things that strings know how to do.

[Metalhead]

Thanks for all the help, but one last question!!!
Now, even if the name is entered correctly and assigned to namestring, the age value is not altered.
Any ideas?

Thanks,
Tim

[Metalhead]

I had given age an initial value age = 0 at the start of the program, but this isn't in the loop by the way

tim

[bartonc]

I had given age an initial value age = 0 at the start of the program, but this isn't in the loop by the way

tim

Post you program. Be sure to use code tags. It's probably a matter of scope. The scope of a variable (global or local) depends on where/how you declare/assign it.

aGlobal = 100
def func():
    aLocal = 100
func()
print aLocal
Traceback (most recent call last):
File "<pyshell#0>", line 1, in -toplevel-
    print aLocal
NameError: name 'aLocal' is not defined
 

See what I mean?

[Metalhead]

Hi,
This is the code. I was just playing around with a simple program that would amuse kids and would teach me about using
simple loops.
the age value always seems to be 0. I would also like a bit of code to ask the name again if the wrong name was input.

thanks!!!

from time import sleep
age = 0
print 'hello'
sleep(5)
print 'I bet I can tell whether you are telling the truth about how old you are ?'
sleep(5)
print 'I CAN prove it to you'
sleep(5)
print 'You still dont believe me, do you?'
namestring = raw_input("WHAT IS YOUR NAME?" )
namestring = namestring.capitalize()
if namestring == 'Jack':
    age = 9
if namestring == 'Rachel':
    age = 7
answer = 0
while answer != age:
    answer=input ("What is your age? ")
    if answer != age:
        print "YOU ARE FIBBING"
print 'NOW YOU ARE TELLING THE TRUTH'
 

[Metalhead]

By the way, I think the names should be capitalized, but there is no difference when i do this.
t

[bartonc]

By the way, I think the names should be capitalized, but there is no difference when i do this.
t

The code ran for me. It looks good too. Try this:

from time import sleep
age = 0
print 'hello'
sleep(5)
print 'I bet I can tell whether you are telling the truth about how old you are ?'
sleep(5)
print 'I CAN prove it to you'
sleep(5)
print 'You still dont believe me, do you?'
namestring = raw_input("WHAT IS YOUR NAME?" ) 
### debug using print
print namestring 
### debug using print
namestring = namestring.capitalize() 
### debug using print
print namestring 
### debug using print
if namestring == 'Jack':
    age = 9
if namestring == 'Rachel':
    age = 7 
### debug using print
print namestring, age 
### debug using print
answer = 0
while answer != age:
    answer=input ("What is your age? ")
    if answer != age:
        print "YOU ARE FIBBING"
print 'NOW YOU ARE TELLING THE TRUTH'
 

Using print statements is a really good way to debug your code.

[Metalhead]

Thanks for all the help. You've been patient!!!

Heres something funny. I copied your code with debug points into a new window, saved it as a new file and ran it. It worked fine. Then I took all of your debug points out and ran it again. It worked perfectly.
Then I loaded my original code and it wouldn't run, yet line by line it looks exactly the same. I can't explain that I'm afraid :-)

Thanks again

p.s. I'm only getting back into programming after a LOT of years away. Back then the Commodore Vic-20 was king and programmers could manage to write games like frogger with its 'huge' 5K (3.5K useable) of free memory :-) I could actually churn out a reasonable program myself believe it or not!!!!

[Metalhead]

If you do't mind being patient once more, can this be simplified :-

if namestring != 'Rachel' and namestring != 'Jack' and namestring != '':

[bartonc]

If you do't mind being patient once more, can this be simplified :-

if namestring != 'Rachel' and namestring != 'Jack' and namestring != '':

I don't mind at all. That's what we're here for.
This can be simplified in a very cool and extensible way using a list:

people = ['Jack', 'Rachel']
if namestring not in people:
    # do stuff for unknown people
 

The in operator is the same a writing a function like this:

def IsInList(key, list):    # Return True if key is in list
    for item in list:
        if key == item:
            return True
 

in works on most iterators (lists, dictionaries, file objects, etc) in all sorts of cool ways.
I guess that you know what not does.

[bartonc]

I don't mind at all. That's what we're here for.
This can be simplified in a very cool and extensible way using a list:

people = ['Jack', 'Rachel']
if namestring not in people:
    # do stuff for unknown people
 

The in operator is the same a writing a function like this:

def IsInList(key, list):    # Return True if key is in list
    for item in list:
        if key == item:
            return True
 

in works on most iterators (lists, dictionaries, file objects, etc) in all sorts of cool ways.
I guess that you know what not does.

The equivalent function above uses the in operator (I do it without thinking) as a generator so that we don't write functions like this:

for i in range(len(aList)):    # There's in again, can't get away from it!
    yeild aList[i]