plot with unsorted indices misses data points

[den-run-ai]

Compare these 2 plots below, this is not expected behavior:

import pandas as pd
from numpy.random import rand
testarr1=rand(100)
testarr2=rand(100)
pd.DataFrame(testarr2,index=testarr1).plot(style='.')
pd.DataFrame(testarr2,index=testarr1).sort().plot(style='.')

[sinhrks]

Are you reporting a different issue from stackoverflow?

The difference seems to be caused by xlim adjustment logic. A workaround is:

ax = pd.DataFrame(testarr2,index=testarr1).plot(style='.')
ax.set_xlim(0, 1)

PR is welcome.

[den-run-ai]

I removed SO question, it is completely unrelated after more detailed reading.
Setting xlim is a better workaround than sort.

[yoavram]

Another example with real data, gist contains a short notebook and the data.

@sinhrks can you point me towards where xlim adjustment logic is?

[jreback]

@TomAugspurger ?

[TomAugspurger]

@yoavram I believe the issue is somewhere around here

pandas/pandas/tools/plotting.py

Line 3569 in c112252

x = l.get_xdata(orig=False)

That seems to assume x[0] is the left-most /smallest point, and x[-1] is the largest. Presumably, you could call np.min and max on those rather than assuming that it's already sorted. Are you able to make a PR with a fix and test?

[yoavram]

I'll have a go at it, but I wonder how to test it - get the data from the aces and check that xlim contains the data range ?

[TomAugspurger]

Maybe just to 2 plots, one sorted and the other not, and assert that they have the same xlim? That may work.

…

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