QST: I receive a message from pandas which is "FutureWarning: PeriodDtype[B] is deprecated and will be removed in a future version. Use a DatetimeIndex with freq='B' instead"

[Jacques2101]

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I receive a message from pandas 2.1.1 for which I don't know how to react. it is "FutureWarning: PeriodDtype[B] is deprecated and will be removed in a future version. Use a DatetimeIndex with freq='B' instead"
What should I do ?

[lithomas1]

Can you post a minimum reproducible example with code?

[Jacques2101]

i have data that are like this:

Amundi energies Vertes SAS | Amundi Euroland Eq Dyn MultiFact A EUR C | Amundi Bavarian Equity Fund I-C/D
-- | -- | --

99.79 | 123.03 | 139.03
99.79 | 122.72 | 138.20
99.79 | 122.44 | 138.21
99.79 | 122.16 | 137.75
99.79 | 121.50 | 137.43
99.79 | 121.15 | 136.23
99.79 | 121.57 | 136.30
99.79 | 122.10 | 136.79
99.79 | 121.75 | 136.20
99.79 | 121.38 | 135.61
99.79 | 122.74 | 136.97
99.99 | 123.17 | 137.85
NaN | 121.95 | 136.03
NaN | 122.10 | 135.25
NaN | 123.13 | 136.53
NaN | 121.60 | 134.72
NaN | 121.24 | 134.97
NaN | 120.24 | 133.52
NaN | 119.33 | 132.45

I must add that my data is generated by a function:

def data(...):
   # Data generates from other dataframe
   df['date'] = pd.to_datetime(df['date'])
   return df.set_index('date').asfreq('b')

and i do:
df.plot();

and then I get message (but the graph also!)

/Users/jacques/opt/anaconda3/envs/data/lib/python3.10/site-packages/matplotlib/axis.py:1732: FutureWarning: Period with BDay freq is deprecated and will be removed in a future version. Use a DatetimeIndex with BDay freq instead.
  ret = self.converter.convert(x, self.units, self)
/Users/jacques/opt/anaconda3/envs/data/lib/python3.10/site-packages/matplotlib/axis.py:1732: FutureWarning: PeriodDtype[B] is deprecated and will be removed in a future version. Use a DatetimeIndex with freq='B' instead
  ret = self.converter.convert(x, self.units, self)
/Users/jacques/opt/anaconda3/envs/data/lib/python3.10/site-packages/matplotlib/axis.py:1732: FutureWarning: PeriodDtype[B] is deprecated and will be removed in a future version. Use a DatetimeIndex with freq='B' instead
  ret = self.converter.convert(x, self.units, self)
/Users/jacques/opt/anaconda3/envs/data/lib/python3.10/site-packages/matplotlib/axis.py:1732: FutureWarning: PeriodDtype[B] is deprecated and will be removed in a future version. Use a DatetimeIndex with freq='B' instead
  ret = self.converter.convert(x, self.units, self)
/Users/jacques/opt/anaconda3/envs/data/lib/python3.10/site-packages/matplotlib/axis.py:1484: FutureWarning: Period with BDay freq is deprecated and will be removed in a future version. Use a DatetimeIndex with BDay freq instead.
  return self.major.locator()
/Users/jacques/opt/anaconda3/envs/data/lib/python3.10/site-packages/matplotlib/axis.py:1484: FutureWarning: PeriodDtype[B] is deprecated and will be removed in a future version. Use a DatetimeIndex with freq='B' instead
  return self.major.locator()
/Users/jacques/opt/anaconda3/envs/data/lib/python3.10/site-packages/matplotlib/ticker.py:218: FutureWarning: Period with BDay freq is deprecated and will be removed in a future version. Use a DatetimeIndex with BDay freq instead.
  return [self(value, i) for i, value in enumerate(values)]

[mroeschke]

Thanks for the report. This is being addressed in #55138 so closing

[Jacques2101]

I am not sure I understand what should I do to not get this message ???? Because when I replace: ``` def data(...): # Data generates from other dataframe df['date'] = pd.to_datetime(df['date']) return df.set_index('date').asfreq('b') ``` with: ``` def data(...): # Data generates from other dataframe df['date'] = pd.to_datetime(df['date']) return df.set_index('date') #delete asfreq('b') ``` i do not have any warning message.

[mroeschke]

You can filter warnings for now while this is being fixed

[amanlai]

@Jacques2101 Period with freq='B' is being deprecated; that's why removing asfreq('b') "solves" the issue; although when you do that, the plot will look different.

You can filter this specific warning by running: warnings.filterwarnings(action='ignore', category=FutureWarning, message=r".*Use a DatetimeIndex.*"). See this post for a working example.