Unhandled warning from NumPy dev in median

[TomAugspurger]

In [1]: import pandas as pd

In [2]: import numpy as np

In [3]: x = np.random.randn(30, 4)

In [4]: x[5:10] = np.nan

In [5]: pd.DataFrame(x).median(1).head()
/Users/taugspurger/miniconda3/envs/travis-37-numpydev/lib/python3.7/site-packages/numpy/lib/function_base.py:3267: RuntimeWarning: All-NaN slice encountered
  r = func(a, **kwargs)
Out[5]:
0   -0.602415
1   -0.118699
2    0.744368
3   -0.993376
4   -0.304693
dtype: float64

In [6]: np.__version__
Out[6]: '1.16.0.dev0+88cbd3d'

Do we want to silence these?

Working around this in #22699

[mroeschke]

I don't imagine this is much of an issue anymore. On 1.18.1 no warning is issued. Closing for now but happy to reopen.

In [1]: np.__version__
Out[1]: '1.18.1'

In [2]: In [1]: import pandas as pd
   ...:
   ...: In [2]: import numpy as np
   ...:
   ...: In [3]: x = np.random.randn(30, 4)
   ...:
   ...: In [4]: x[5:10] = np.nan
   ...:
   ...: In [5]: pd.DataFrame(x).median(1).head()
Out[2]:
0   -0.155427
1   -0.317316
2    0.752829
3    0.366792
4   -0.155743
dtype: float64

[ivangvi]

Hi! I stumbled across this issue while doing several aggregations, sum, mean and so on. Median gives me warning and I believe I'd like to avoid it. With the following line you should be able to reproduce the warning:

pd.DataFrame(data = {'a':[np.NaN,2,3],'b':[np.NaN,3,3]}).agg('median',axis = 1)

\lib\site-packages\numpy\lib\nanfunctions.py:1116: RuntimeWarning: All-NaN slice encountered
  overwrite_input=overwrite_input)

Thank you.