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Re: Rounding off Values of dicts (in a list) to 2 decimal points

From Jussi Piitulainen <jpiitula@ling.helsinki.fi>
Newsgroups comp.lang.python
Subject Re: Rounding off Values of dicts (in a list) to 2 decimal points
Date 2013-10-02 20:22 +0300
Organization University of Helsinki
Message-ID <qotpprnio5g.fsf@ruuvi.it.helsinki.fi> (permalink)
References <0aa3c507-a570-4d39-823d-106ba63b0b70@googlegroups.com>

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tripsvt@gmail.com writes:

>  am trying to round off values in a dict to 2 decimal points but
>  have been unsuccessful so far. The input I have is like this:
> 
>     y = [{'a': 80.0, 'b': 0.0786235, 'c': 10.0, 'd': 10.6742903},
>     {'a': 80.73246, 'b': 0.0, 'c': 10.780323, 'd': 10.0}, {'a':
>     80.7239, 'b': 0.7823640, 'c': 10.0, 'd': 10.0}, {'a':
>     80.7802313217234, 'b': 0.0, 'c': 10.0, 'd': 10.9762304}]
> 
> I want to round off all the values to two decimal points using the
> ceil function. Here's what I have:
> 
>     def roundingVals_toTwoDeci():
>         global y
>         for d in y:
>             for k, v in d.items():
>                 v = ceil(v*100)/100.0
>         return
>     roundingVals_toTwoDeci()
> 
> But it is not working - I am still getting the old values.

You are assigning to a local variable, v. Instead, store the new
values back to the dict like this:

   d[k] = ceil(v*100)/100.0

And you don't need to declare y global. It would only be needed if you
assigned directly to it, as in y = ... (usually not a good idea).

The rounding may not work the way you expect, because float values are
stored in binary. You may need a decimal type, or you may need to
format the output when printing instead.

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Thread

Rounding off Values of dicts (in a list) to 2 decimal points tripsvt@gmail.com - 2013-10-02 10:01 -0700
  Re: Rounding off Values of dicts (in a list) to 2 decimal points Skip Montanaro <skip@pobox.com> - 2013-10-02 12:13 -0500
  Re: Rounding off Values of dicts (in a list) to 2 decimal points Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-10-02 20:22 +0300
  Re: Rounding off Values of dicts (in a list) to 2 decimal points Joel Goldstick <joel.goldstick@gmail.com> - 2013-10-02 13:19 -0400
  Re: Rounding off Values of dicts (in a list) to 2 decimal points Neil Cerutti <neilc@norwich.edu> - 2013-10-02 17:32 +0000
  Re: Rounding off Values of dicts (in a list) to 2 decimal points tripsvt@gmail.com - 2013-10-03 10:06 -0700
    Re: Rounding off Values of dicts (in a list) to 2 decimal points Peter Otten <__peter__@web.de> - 2013-10-03 19:41 +0200
    Re: Rounding off Values of dicts (in a list) to 2 decimal points Neil Cerutti <neilc@norwich.edu> - 2013-10-03 18:03 +0000
      Re: Rounding off Values of dicts (in a list) to 2 decimal points tripsvt@gmail.com - 2013-10-03 11:17 -0700

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