[Tutor] flow problem with a exercise

[Roelof Wobben]

From: waynejwerner at gmail.com
Date: Fri, 20 Aug 2010 15:07:56 -0500
Subject: Re: [Tutor] flow problem with a exercise
To: rwobben at hotmail.com
CC: tutor at python.org


On Fri, Aug 20, 2010 at 2:48 PM, Roelof Wobben <rwobben at hotmail.com> wrote:


Oke, 
 
I don''t understand it complety.
 
return not arg%2 
 
Why use not here ?
 
I think that arg%2 is True not makes it false. 



What happens when you replace arg with a value? % is modulo division, so it just returns the remainder.


2 % 2 = ?
2%2=0 
 
4 % 2 = ?
4%2=0
 
7 % 2 = ?
 
7%2=1 
 
11 % 2 = ?
 
11%2 =1 

What is the truth value of 0 and 1?


print 'True' if 0 else 'False'
 
False 
 
print 'True' if 1 else 'False'
 
True

So what is the outcome of the following?


result = 2 % 2
print result, not result
if not result:
   print 'Even'
if result:
   print 'odd'
 
0  True
Even 
 
So 1 is True and 0 is False according to Python.


 

 
Another question.
 
How can I round outcome of a calculation.
 
round ( ( t-32)/1.8) does not work because I get a message that there are two arguments.
 
Outcome = (t-32)/1.8
outcome2 = round (outcome) does not work because the argument must be a string or a number 


What is the type of t?


 In [39]: t = 3


In [40]: round((t-32)/1.8)
Out[40]: -16.0


In [41]: t = 3.0


In [42]: round((t-32)/1.8)
Out[42]: -16.0


Works fine for me.
 
Correct, 
But I see one wierd thing.
 
round ((42-32)/1.8) gives a output -16.0 but (42-32)/1.8) gives also -16.0 
I was expectting that round will give 16 as output because round (32.0) is the same as round (32.0, 0) so there will be 0 decimals.
And I see one decimal.
 
Roelof
 


HTH,
Wayne 		 	   		  
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