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[khaosyt at gmail.com]

On Monday, April 1, 2013 8:00:30 PM UTC-4, Steven D'Aprano wrote:
> On Mon, 01 Apr 2013 14:44:45 -0700, khaosyt wrote:
> 
> 
> 
> > If I wanted to get the sum of some numbers (for example: 1 + 2 + 3 + 4 +
> 
> > 5 = 15) from the attached program what do I do? Keep in mind that the
> 
> > print statement prints the integers individually.
> 
> 
> 
> 
> 
> Yes, we know what the print statement does. Some of us have been using 
> 
> Python for weeks now.
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> 
> 
> 
> 
> Some comments interspersed within your code below:
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> 
> 
> 
> 
> 
> 
> > integer = 0
> 
> > denom = 10
> 
> > again = "y" #sentinel:
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> 
> 
> Technically, that's not a sentinel.
> 
> 
> 
> > while again == "y" or again == "Y":
> 
> >     integer = input("Enter a positive integer: ")
> 
> 
> 
> I believe that the last time you asked this question, you were told not 
> 
> to use the "input" function as it was dangerous or can lead to hard-to-
> 
> understand bugs. Change the above line to:
> 
> 
> 
>     integer = raw_input("Enter a positive integer: ")
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> 
> 
> 
> 
> Notice that if you do this, the so-called "integer" is actually a string. 
> 
> This is a good thing! You want it as a string, since that makes it easy 
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> to extract individual digits.
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> 
> 
> 
> 
> >     while denom <= integer:
> 
> >         denom = denom*10
> 
> >     while denom > 1:
> 
> >         denom = denom/10
> 
> >         number = integer/denom
> 
> >         integer = integer%denom
> 
> >         print str(number)
> 
> 
> 
> All this stuff with denom seems to be aimed at extracting the digits from 
> 
> a number. There's an easier way: just work with the string.
> 
> 
> 
> After the line I suggested above 
> 
> 
> 
>     integer = raw_input("Enter a positive integer: ")
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> 
> 
> 
> 
> "integer" is a string of digits. So you can iterate over the digits using 
> 
> a for-loop:
> 
> 
> 
> # this is not what you want!
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> for digit in integer:
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>     print digit
> 
> 
> 
> 
> 
> Instead of printing the digits, you want to add them up. So start by 
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> initialising a total, then add them:
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> 
> 
>     total = 0
> 
>     for digit in integer:
> 
>         total = total + digit
> 
> 
> 
> 
> 
> Warning! The above three lines contains a bug. If you make the changes I 
> 
> suggest, and try it, you will get an error. That's okay. Read the error. 
> 
> Try to understand what it is telling you. Hint: remember that total is an 
> 
> actual int, a number, while each digit is a single character, a string.
> 
> 
> 
> You need to convert each digit into a number before adding it. Hint: the 
> 
> int function takes a string, and converts it to a number.
> 
> 
> 
> py> 42 + "23"
> 
> Traceback (most recent call last):
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>   File "<stdin>", line 1, in <module>
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> TypeError: unsupported operand type(s) for +: 'int' and 'str'
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> py> 42 + int("23")
> 
> 65
> 
> 
> 
> 
> 
> This should hopefully give you enough information to get some working 
> 
> code. Try to write as much of the code as you can, and come back with any 
> 
> further questions *after* making a good effort.
> 
> 
> 
> Another hint: try experimenting at the interactive interpreter, or IDLE. 
> 
> If you're unsure about something, try it and see what happens *before* 
> 
> asking.
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> 
> 
> 
> 
> Good luck.
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> 
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> 
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> 
> 
> -- 
> 
> Steven

Thanks. I'll try it out.