round/float question

[Hans Nowak]

Jason Tesser wrote:
> I am using Rekall which uses Python as it's scripting language  and I have a question about Python.  I am developing a POS system and am working on 
> the checkout form. I pass a parameter named SaleID and another one named Total.  I am trying to take total and convert it to a float with 2 decimals top be used as money obviously.  What would be the proper syntax for this?  I tried Total = round(Total [, 2]) i also tried that with float.  

round() works fine:

 >>> x = 1.2345678
 >>> round(x, 2)
1.23
 >>>

However, issues with floating point representation might show a different 
result.  (The tutorial has a section that explains this in detail.)

 >>> x = 3.141592
 >>> round(x, 2)
3.1400000000000001
 >>>

If that is the problem, use str():

 >>> y = round(x, 2)
 >>> y
3.1400000000000001
 >>> str(y), repr(y)
('3.14', '3.1400000000000001')
 >>>

Or use a format string to display the float in the format you want:

 >>> "%.2f" % (x,)
'3.14'
 >>>

HTH,

-- 
Hans (hans at zephyrfalcon.org)
http://zephyrfalcon.org/