How to show percentage

[Sen-Lung Chen]

Dear All:
I have a question of show percentage.
For example ,I want to show the percentage of 1/3 = 33.33%

I use the 1*100/3 = 33
it is 33 not 33.33 , how to show the 33.33 %
Thanks

[dylan.moreland@gmail.com]

Re: How to show percentage

Traditionally, one part of the expression has to be a float for the
result to be a float (this is a holdover from C). So 100/3.0 will give
you the result you want. Alternatively, you can put "from __future__
import division" at the top of your script, and then 100/3 will return
a float.

http://www.python.org/doc/2.2.3/whatsnew/node7.html

[Bill Mill]

Re: How to show percentage

You need to convert 1 or 3 to a float. How about:
[color=blue][color=green][color=darkred]
>>> def pct(num, den): return (float(num)/den) * 100[/color][/color][/color]
....[color=blue][color=green][color=darkred]
>>> pct(1, 3)[/color][/color][/color]
33.333333333333 329

Peace
Bill Mill
bill.mill at gmail.com

On 22 Sep 2005 10:51:43 -0700, Sen-Lung Chen
<slchen@slugger .ee.nthu.edu.tw > wrote:[color=blue]
> Dear All:
> I have a question of show percentage.
> For example ,I want to show the percentage of 1/3 = 33.33%
>
> I use the 1*100/3 = 33
> it is 33 not 33.33 , how to show the 33.33 %
> Thanks
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>[/color]

[Mike Meyer]

Re: How to show percentage

"Sen-Lung Chen" <slchen@larc.ee .nthu.edu.tw> writes:
[color=blue]
> Dear All:
> I have a question of show percentage.
> For example ,I want to show the percentage of 1/3 = 33.33%
>
> I use the 1*100/3 = 33
> it is 33 not 33.33 , how to show the 33.33 %[/color]

Python interprets '/' in an integer environment to return ints, not
floats. You can either turn one of your arguments into floats:
[color=blue][color=green][color=darkred]
>>> float(1 * 100) / 3[/color][/color][/color]
33.333333333333 336

This is going to change. Not sure when. You can ask for the new behavior:
[color=blue][color=green][color=darkred]
>>> from __future__ import division
>>> 100 / 3[/color][/color][/color]
33.333333333333 336

<mike

--
Mike Meyer <mwm@mired.or g> http://www.mired.org/home/mwm/
Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.

[George Sakkis]

Re: How to show percentage

"Sen-Lung Chen" <slchen@larc.ee .nthu.edu.tw> wrote:[color=blue]
> Dear All:
> I have a question of show percentage.
> For example ,I want to show the percentage of 1/3 = 33.33%
>
> I use the 1*100/3 = 33
> it is 33 not 33.33 , how to show the 33.33 %
> Thanks[/color]

"%.2f%%" % (100./3.)

Not quite the most readable expression in python.. ;)

George

[Terry Hancock]

Re: How to show percentage

On Thursday 22 September 2005 12:51 pm, Sen-Lung Chen wrote:[color=blue]
> Dear All:
> I have a question of show percentage.
> For example ,I want to show the percentage of 1/3 = 33.33%
>
> I use the 1*100/3 = 33
> it is 33 not 33.33 , how to show the 33.33 %
> Thanks[/color]

In addition to needing a floating point value as other
posters have noted, you're going to need a format string,
e.g.:[color=blue][color=green][color=darkred]
>>> print "%5.2f%%" % (100.0/3)[/color][/color][/color]
33.33%

Note the need to escape "%" as it is normally the format
specifier character.

Cheers,
Terry

--
Terry Hancock ( hancock at anansispacework s.com )
Anansi Spaceworks http://www.anansispaceworks.com

[Steve Holden]

Re: How to show percentage

Sen-Lung Chen wrote:[color=blue]
> Dear All:
> I have a question of show percentage.
> For example ,I want to show the percentage of 1/3 = 33.33%
>
> I use the 1*100/3 = 33
> it is 33 not 33.33 , how to show the 33.33 %
> Thanks
>[/color]
You should by now know enough answers. The easiest way to ensure that
the result is floating point is to cast it as

pct = 100.0 * v) / N

This is guaranteed to work in all past and future Python versions
without setting any options. Then you can format is using the % operator.

regards
Steve
--
Steve Holden +44 150 684 7255 +1 800 494 3119
Holden Web LLC www.holdenweb.com
PyCon TX 2006 www.pycon.org

[Steve Holden]

Re: How to show percentage

Steve Holden wrote:[color=blue]
> Sen-Lung Chen wrote:
>[color=green]
>>Dear All:
>> I have a question of show percentage.
>>For example ,I want to show the percentage of 1/3 = 33.33%
>>
>> I use the 1*100/3 = 33
>>it is 33 not 33.33 , how to show the 33.33 %
>> Thanks
>>[/color]
>
> You should by now know enough answers. The easiest way to ensure that
> the result is floating point is to cast it as
>
> pct = 100.0 * v) / N
>
> This is guaranteed to work in all past and future Python versions
> without setting any options. Then you can format is using the % operator.
>
> regards
> Steve[/color]

.... apart from the obvious syntax error, that is. Sigh.

pct = (100.0 * v) / N

regards
Steve
--
Steve Holden +44 150 684 7255 +1 800 494 3119
Holden Web LLC www.holdenweb.com
PyCon TX 2006 www.pycon.org