Unsorted Float64Index gives clipped plots

[fuglede]

Code Sample, a copy-pastable example if possible

import pandas as pd
df = pd.DataFrame({'y': [3.5, 4.5, 6.5]}, index=[2.5, 1.5, 3.5])
df.plot(style='o')

Problem description

This above may or may not be expected behaviour, but it did catch me by surprise: The range of the horizontal axis will be [2.5, 3.5], even though one of the data points has an index value outside that range.

Expected Output

Instead, I would have expected the output currently obtainable through df.sort_index().plot(style='o'):

Output of pd.show_versions()

INSTALLED VERSIONS

commit: None
python: 3.6.2.final.0
python-bits: 64
OS: Windows
OS-release: 8.1
machine: AMD64
processor: Intel64 Family 6 Model 61 Stepping 4, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None

pandas: 0.20.3
pytest: 3.2.1
pip: 9.0.1
setuptools: 34.1.0
Cython: 0.26
numpy: 1.13.1
scipy: 0.19.1
xarray: None
IPython: 6.1.0
sphinx: 1.6.2
patsy: 0.4.1
dateutil: 2.6.1
pytz: 2017.2
blosc: None
bottleneck: 1.2.1
tables: 3.2.2
numexpr: 2.6.2
feather: None
matplotlib: 2.0.2
openpyxl: 2.4.8
xlrd: 1.0.0
xlwt: 1.2.0
xlsxwriter: 0.9.8
lxml: 3.8.0
bs4: 4.6.0
html5lib: 0.9999999
sqlalchemy: 1.1.13
pymysql: None
psycopg2: None
jinja2: 2.9.6
s3fs: None
pandas_gbq: None
pandas_datareader: 0.5.0

[bobhaffner]

I tested this in the latest master branch and it matches your expected output.

This means that this will be fixed in the next release

I believe this commit fixed it #16600

[jreback]

@bobhaffner is there a test for this in master? if not would u do a PR for one?

[bobhaffner]

Hi @jreback, Yes, I'll check it out

[bobhaffner]

@jreback It looks like test_unsorted_index_lims covers this case

[jreback]

thanks!

[bobhaffner]

No problem @jreback Thanks for closing this, @TomAugspurger

[fuglede]

And thanks for looking into it; indeed, it looks like this one was a duplicate of #11471.