[Matplotlib] Ploting an exponential distribution frequency curve

From	Mario Figueiredo <marfig@gmail.com>
Newsgroups	comp.lang.python
Subject	[Matplotlib] Ploting an exponential distribution frequency curve
Date	2015-04-25 23:33 +0100
Organization	Aioe.org NNTP Server
Message-ID	<bi4ojap79mlcjq05skiar1ftrfh42j3efh@4ax.com> (permalink)

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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.

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[Matplotlib] Ploting an exponential distribution frequency curve Mario Figueiredo <marfig@gmail.com> - 2015-04-25 23:33 +0100
  Re: [Matplotlib] Ploting an exponential distribution frequency curve Mario Figueiredo <marfig@gmail.com> - 2015-04-25 23:36 +0100
    Re: [Matplotlib] Ploting an exponential distribution frequency curve Mario Figueiredo <marfig@gmail.com> - 2015-04-26 00:15 +0100
      Re: [Matplotlib] Ploting an exponential distribution frequency curve John Ladasky <john_ladasky@sbcglobal.net> - 2015-04-25 22:08 -0700
      Re: [Matplotlib] Ploting an exponential distribution frequency curve Dave Farrance <DaveFarrance@OMiTTHiSyahooANDTHiS.co.uk> - 2015-04-26 11:17 +0100
        Re: [Matplotlib] Ploting an exponential distribution frequency curve Mario Figueiredo <marfig@gmail.com> - 2015-04-26 13:32 +0100
  Re: [Matplotlib] Ploting an exponential distribution frequency curve Denis McMahon <denismfmcmahon@gmail.com> - 2015-04-25 23:12 +0000
    Re: [Matplotlib] Ploting an exponential distribution frequency curve Mario Figueiredo <marfig@gmail.com> - 2015-04-26 00:35 +0100
  Re: [Matplotlib] Ploting an exponential distribution frequency curve Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-04-26 01:31 +0100
  Re: [Matplotlib] Ploting an exponential distribution frequency curve Denis McMahon <denismfmcmahon@gmail.com> - 2015-04-26 18:55 +0000
    Re: [Matplotlib] Ploting an exponential distribution frequency curve Mario Figueiredo <marfig@gmail.com> - 2015-04-26 20:57 +0100

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