date_ Range creation date range freq parameter value table and creation example

>>> r=pd.date_range(start='1999-12-01',end='1999-12-31')
>>> print(r)
DatetimeIndex(['1999-12-01', '1999-12-02', '1999-12-03', '1999-12-04',
               '1999-12-05', '1999-12-06', '1999-12-07', '1999-12-08',
               '1999-12-09', '1999-12-10', '1999-12-11', '1999-12-12',
               '1999-12-13', '1999-12-14', '1999-12-15', '1999-12-16',
               '1999-12-17', '1999-12-18', '1999-12-19', '1999-12-20',
               '1999-12-21', '1999-12-22', '1999-12-23', '1999-12-24',
               '1999-12-25', '1999-12-26', '1999-12-27', '1999-12-28',
               '1999-12-29', '1999-12-30', '1999-12-31'],
              dtype='datetime64[ns]', freq='D')

>>> r=pd.date_range(start='1999-12-01',end='1999-12-31',freq='B')
>>> print(r)
DatetimeIndex(['1999-12-01', '1999-12-02', '1999-12-03', '1999-12-06',
               '1999-12-07', '1999-12-08', '1999-12-09', '1999-12-10',
               '1999-12-13', '1999-12-14', '1999-12-15', '1999-12-16',
               '1999-12-17', '1999-12-20', '1999-12-21', '1999-12-22',
               '1999-12-23', '1999-12-24', '1999-12-27', '1999-12-28',
               '1999-12-29', '1999-12-30', '1999-12-31'],
              dtype='datetime64[ns]', freq='B')

>>> r=pd.date_range(start='1999-12-01',end='1999-12-31',freq='BM')
>>> print(r)
DatetimeIndex(['1999-12-31'], dtype='datetime64[ns]', freq='BM'

>>> r=pd.date_range(start='1999-1-01',end='1999-12-31',freq='BQS')
>>> print(r)
DatetimeIndex(['1999-01-01', '1999-04-01', '1999-07-01', '1999-10-01'], dtype='datetime64[ns]', freq='BQS-JAN')

Offset parameter

date_range There is a parameter in the freq, Used to select from the range you specify , You can choose working days （B）、 At the beginning of （MS）、 Month end working day （BM）、 The working day at the beginning of the quarter （BQS） etc. .

Alias	explain
B	Working day
C	Custom weekdays （ experiment ）
D	Calendar day
W	Once a week
M	end of the month
SM	Mid month and end of month （ The 15th day and the end of each month ）
BM	Month end working day
CBM	Customize month end workdays
MS	At the beginning of
SMS	The beginning of the month and the middle of the month （ The first and fifteenth days of each month ）
BMS	Working day at the beginning of the month
CBMS	Customize the working day at the beginning of the month
Q	Quarter end
BQ	Quarter end business day
QS	Beginning of quarter
BQS	The working day at the beginning of the quarter
A	end of the year
BA	Working days at the end of the year
AS	Beginning of the year
BAS	Working days at the beginning of the year
BH	working hours
H	Hours
T	minute
S	second
L	millisecond
U	Microsecond
N	nanosecond