[Tutor] string integers?

[William Stewart]

Thank you for the reply It worked fine !

--- On Sun, 2/12/12, Steven D'Aprano <steve at pearwood.info> wrote:


From: Steven D'Aprano <steve at pearwood.info>
Subject: Re: [Tutor] string integers?
To: tutor at python.org
Date: Sunday, February 12, 2012, 6:50 PM


William Stewart wrote:
> this is the code I have
>  str1 = raw_input("Type in a String: ")
> str2 = raw_input("Type in a String: ")
> int1 = raw_input("Type in a integer variable: ")
> int2 = raw_input("Type in a integer variable: ")
> print str1 + str2 + int1 + int2
> import math
> int1 = int(raw_input(""))
> print str1,
> print str2,
> print int1, "*", int2
> print "="
> 
> and it does not give me an error message when I run it, the program runs fine
>  except its did not multiply the 2 integer variables i entered


But you haven't asked it to multiply anything. You asked it to PRINT the two variables with an asterisk between them.

And further more, you don't have two integers. You have two strings that merely happen to contain digits. Before you can do maths on them, you have to tell Python to treat them as integers, not strings. You use the int() function (int being short for integer, in case it isn't obvious) for that:


py> x = raw_input("Enter a number: ")
Enter a number: 42
py> type(x)
<type 'str'>
py> x * 10
'42424242424242424242'
py>
py> x + 1
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: cannot concatenate 'str' and 'int' objects


Before you can do maths on x, you have to turn it into a number:

py> x = int(x)
py> x * 10
420
py> x + 1
43


P.S. Does your computer have a Delete or Backspace key? Please trim your replies, there is no need to quote page after page after page of old conversation that you don't directly address.




-- Steven

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