[Matplotlib] Ploting an exponential distribution frequency curve

Mark Lawrence breamoreboy at yahoo.co.uk
Sun Apr 26 02:31:16 CEST 2015


On 25/04/2015 23:33, Mario Figueiredo wrote:
> I'm trying to plot the curve of an exponential distribution without
> much success. I'm missing something very basic I feel, but just can't
> figure it out after numerous tries, so I'm turning out to you.
>
> This is the function generating the frequency of individual outcomes:
>
>      import decimal
>      from random import expovariate
>      from collections import defaultdict
>
>      decimal.getcontext().prec = 4
>      Dec = decimal.Decimal
>
>      samples = 100000   # 100,000
>
>      def generate(lambd):
>          res = defaultdict(int)
>          for _ in range(samples):
>              res[Dec(expovariate(lambd)).quantize(Dec('0.01'))] += 1
>          return res
>
> Trying to plot this data into a frequency curve is proving too
> challenging and I just can't understand why.
>
>      plot(list(results.keys()), list(results.values()))
>
> This results in strange line graph where there is the outline of an
> exponential curve but the line crisscrosses all over the place. I
> can't understand why I am getting this graph result and not just the
> smooth line I can infer from looking at the hard data.
>

Anything that can hep you here 
http://matplotlib.org/gallery.html#statistics ?

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence




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