Pandas date_range to generate monthly data at beginning of the month

Question

I\'m trying to generate a date range of monthly data where the day is always at the beginning of the month:

pd.date_range(start=\'1/1/1980\', end=\'11/1/1991         


        

Answer 1

You can do this by changing the freq argument from 'M' to 'MS':

d = pandas.date_range(start='1/1/1980', end='11/1/1990', freq='MS')    
print(d)

This should now print:

DatetimeIndex(['1980-01-01', '1980-02-01', '1980-03-01', '1980-04-01',
               '1980-05-01', '1980-06-01', '1980-07-01', '1980-08-01',
               '1980-09-01', '1980-10-01', 
               ...
               '1990-02-01', '1990-03-01', '1990-04-01', '1990-05-01',
               '1990-06-01', '1990-07-01', '1990-08-01', '1990-09-01',
               '1990-10-01', '1990-11-01'],
              dtype='datetime64[ns]', length=131, freq='MS', tz=None)

Look into the offset aliases part of the documentation. There it states that 'M' is for the end of the month (month end frequency) while 'MS' for the beginning (month start frequency).