[Idle-dev] output improper

[Tal Einat]

Mayuresh Marathe wrote:

>  Dear Sir,
>
>
>
> I would request kind help in sorting a problem out as I am getting improper
> results. I am pasting the program and its output for reference.
>
>
>
> Python 3.1.1 (r311:74483, Aug 17 2009, 17:02:12) [MSC v.1500 32 bit
> (Intel)] on win32
>
> Type "copyright", "credits" or "license()" for more information.
>
> >>> print ("Please give a number: ")
>
> Please give a number:
>
> >>> a = input()
>
> 12
>
> >>> Print ("And another :")
>
> Traceback (most recent call last):
>
>   File "<pyshell#2>", line 1, in <module>
>
>     Print ("And another :")
>
> NameError: name 'Print' is not defined
>
> >>> print ("And another: ")
>
> And another:
>
> >>> b = input()
>
> 23
>
> >>> print ("The sum of these numbers is :")
>
> The sum of these numbers is :
>
> >>> print (a+b)
>
> 1223
>
> >>> print a+b
>
> SyntaxError: invalid syntax (<pyshell#7>, line 1)
>
> >>> print("a+b")
>
> a+b
>
> >>> print (a+b)
>
> 1223
>
> >>>
>

Hello Mayuresh,

In version 3.0 and above of Python, the input() function always returns a
string. To get what you want, pass the strings returned by input() into the
int() function in order to convert them to integers, for example:

>>> a = int(input())

In your above example, both 'a' and 'b' are variables referring to strings,
not numbers. In Python, "adding" strings means concatenation, for example
"abc" + "ecf" will become the string "abcdef", and similarly "12" + "23"
becomes "1223". On the other hand, 12 + 23 becomes 35, since 12 and 23 are
integers (whole numbers).


It is useful to just write the name of a variable and then enter in the
shell, which prints that variable's representation. For example:

>>> a = "12"
>>> b = 12
>>> a
'12'
>>> b
12

>From the output above you can see that the variable 'a' refers to a string,
while the variable 'b' refers to an integer.


Finally, this mailing list is for the discussion of IDLE itself. While I'm
happy to help, general Python questions such as this are better directed to
other places, where you will get more answer more quickly. See
http://wiki.python.org/moin/BeginnersGuide, and specifically
http://wiki.python.org/moin/BeginnersGuide/Help, for details on good places
to get help for beginning with Python. I highly recommend posting on the
comp.lang.python newsgroup, and searching there since answers to most Python
questions are already there!


Good luck!

- Tal
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