How to write string (float) to file?

[Bengt Richter]

On Tue, 28 Aug 2001 15:41:57 GMT, "Rainer Deyke" <root at rainerdeyke.com> wrote:

><gbreed at cix.compulink.co.uk> wrote in message
>news:9mfqmi$ko4$1 at thorium.cix.co.uk...
>> In article <9mfm1l$gs3$1 at zeus.man.szczecin.pl>,
>> piotrlg at sci.pam.szczecin.pl (Piotr Legiecki) wrote:
>>
>> > How can I tell python to give me only 2 digits after decimal point? And
>> > of course store it in a variable.
>> >
>> > So I want 'c' to be 3.33.
>>
>> c = '%.2f'%(float(a)/b)
>
>That's unreliable.  Use this instead:
Unreliable in what sense?
>
>c = (a * 100) / b
>s = '%03d' % c
>file.write(s[:-2] + '.' + s[-2:])
>
Making a function of your logic:

 >>> def foodiv(a,b):
 ...     c = (a * 100) / b
 ...     s = '%03d' %c
 ...     return s[:-2] + '.' + s[-2:]
 ...

 >>> for x in [30,-30,60,-60]: print foodiv(x,9)
 ...
 3.33
 -3.34
 6.66
 -6.67

Is that the reliable results you think he wants? ;-)
Whereas

 >>> for x in [30,-30,60,-60]: print '%.2f'%(float(x)/9)
 ...
 3.33
 -3.33
 6.67
 -6.67

You shouldn't mess with newbie minds like that ;-)