Code Sampledf = pd.DataFrame({'A':['a','b']})df['B'] = Nonedf.groupby('A').B.rank(method='first') # worksdf.B[0] = 1df.g...

Changing the topic with some editing:I stumbled over SettingWithCopyWarning outputting wrong lines when referencing wher...

Code Sample, a copy-pastable example if possibleimport numpy as npimport pandas as pddf = pd.DataFrame(np.random.rand(10...

Problem descriptionI'm searching without success a way to sort the results of pd.Series.str.split.I was expecting a str ...

Hi,it's not a real issue, though I'm having some hard hours because of it. The simple SUMPRODUCT (=weighted average of c...

This was suggested by @MaximilianR here, but @jorisvandenbossche (rightly) proposed to discuss separately.This is relate...

Using the test cases in tests.dtypes.test_generic, checking isinstance(item, ABCIndex) takes ~2x as long as isinstance(i...

Given a timezone-aware Timestamp:foo = pd.Timestamp('2016-10-30 00:00:00', tz=pytz.timezone('Europe/Helsinki'))(Please n...

In the current implementation apply calls func twice on the first column/row to decide whether it can take a fast or slo...

with open("C:\Test\Old.dta", "a") as outfile: a = pd.read_stata("C:\Test\New.dta") a.to_stata(outfile,write_index=...

In [319]: for o in pd.read_msgpack('foo.msg',iterator=True):.....: print o.....:File "<ipython-input-319-a0f40395...

Code Sample, a copy-pastable example if possibleimport pandas as pddf = pd.DataFrame({'x': [1., 5., 3.]}, index=[0, 2, 4...

Caching (memoizing) the date_parser function in read_csv might be an easy perf improvement. Seems it is not cached unles...

p = pd.Panel(data=np.zeros((2, 3, 3)))p.mean(numeric_only=True)<snip></snip>NotImplementedError: Panel.mean ...

Seems like a bug, such a comparison should definitely be allowed. Pandas Version 0.20.2, Ubuntu. In [2]: import pandas a...

Code Sample>>> pd.to_datetime('2017-01-01T15:00:00-05:00')... Timestamp('2017-01-01 20:00:00') # This is a tim...

Hi there,I have a pandas array that contains lists of tuples as shown below: APP_chr21 GRI...

As reported at pendulum, there are cases where creating a date_range fails with a segfault: pendulum issues 131.Code Sam...

When using default to_datetime, without format, the answers is sometimes a bit weird:>>> import pandas as pd&gt...

Code Sample, a copy-pastable example if possible# Your code heredf = pd.read_csv("https://github.com/jennybc/gapmin...