pandas.Series.sort_values(ascending=[False]) behaves as ascending=True

Code Sample, a copy-pastable example if possible

# Your code here
import pandas as pd
x = pd.Series([4,5,6,1,2,3])
print(x.sort_values(ascending=False))
print(x.sort_values(ascending=[False]))

Problem description

False and [False] behave differently. They should behave in the same way according to the documentation (and it makes sense that they do).

Expected Output

2 6 1 5 0 4 5 3 4 2 3 1 dtype: int64 2 6 1 5 0 4 5 3 4 2 3 1 dtype: int64

Output of pd.show_versions()

# Paste the output here pd.show_versions() here INSTALLED VERSIONS ------------------ commit: None python: 3.5.2.final.0 python-bits: 64 OS: Windows OS-release: 7 machine: AMD64 processor: Intel64 Family 6 Model 61 Stepping 4, GenuineIntel byteorder: little LC_ALL: None LANG: en LOCALE: None.None

pandas: 0.19.2 nose: 1.3.7 pip: 9.0.1 setuptools: 27.2.0 Cython: 0.25.2 numpy: 1.11.3 scipy: 0.18.1 statsmodels: 0.6.1 xarray: None IPython: 5.1.0 sphinx: 1.5.1 patsy: 0.4.1 dateutil: 2.6.0 pytz: 2016.10 blosc: None bottleneck: 1.2.0 tables: 3.2.2 numexpr: 2.6.1 matplotlib: 2.0.0 openpyxl: 2.4.1 xlrd: 1.0.0 xlwt: 1.2.0 xlsxwriter: 0.9.6 lxml: 3.7.2 bs4: 4.5.3 html5lib: None httplib2: None apiclient: None sqlalchemy: 1.1.5 pymysql: None psycopg2: None jinja2: 2.9.4 boto: 2.45.0 pandas_datareader: None

[MLopez-Ibanez]

Shouldn’t operations on similar types behave as uniformly as possible? One should not need to know what x is or even what the argument of ascending is, it should just work. Thus, one should be able to write something like:

z.sort_values(ascending = order)

and it should do the right thing whether x is a Series or a 1-column DataFrame. Otherwise, users need to either special case for Series vs. DataFrame or special case for 1-column versus n-columns.

[jreback]

yes would accept a patch and leave the api (iow accept a 1-element list of a boolean); would need a touch of validation

On Mar 7, 2017, at 2:15 PM, MLopez-Ibanez [e-mail] wrote:

Thanks. Does this mean that you may accept a patch making ascending=[False] behave the same as ascending=False ?

I don’t want to waste our time if there is some reason unknown to me why this is undesired behavior. Perhaps there are performance issues in that case that I cannot imagine at the moment.

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