Error with date_range using datetime subselection

Question

I need to create a vector of dates with pd.date_range specifying the min and the max for date values. Date values come from a subselection performed on a dataframe object ds.

This is the code I wrote:

Note that Date in ds are obtained from

ds = pd.read_excel("data.xlsx",sheet_name='all') # Read the Excel file
ds['Date'] = pd.to_datetime(ds['Date'], infer_datetime_format=True) 

This is the part inside a for loop where x loops on a list of Names.

for x in lofNames:
    date_tmp = ds.loc[ds['Security Name']==x,['Date']]
    mindate = date_tmp.min()
    maxdate = date_tmp.max()
    date = pd.date_range(start=mindate, end=maxdate, freq='D')   

This is the error I get:

Traceback (most recent call last):

  File "<ipython-input-8-1f56d07b5a74>", line 4, in <module>
    date = pd.date_range(start=mindate, end=maxdate, freq='D')

  File "/Users/marco/opt/anaconda3/lib/python3.7/site-packages/pandas/core/indexes/datetimes.py", line 1180, in date_range
    **kwargs,

  File "/Users/marco/opt/anaconda3/lib/python3.7/site-packages/pandas/core/arrays/datetimes.py", line 365, in _generate_range
    start = Timestamp(start)

  File "pandas/_libs/tslibs/timestamps.pyx", line 418, in pandas._libs.tslibs.timestamps.Timestamp.__new__

  File "pandas/_libs/tslibs/conversion.pyx", line 329, in pandas._libs.tslibs.conversion.convert_to_tsobject

TypeError: Cannot convert input [Date   2007-01-09
dtype: datetime64[ns]] of type <class 'pandas.core.series.Series'> to Timestamp

What's wrong? thank you

Answer 1

Here is returned one column DataFrame instead Series, so next min and max returned one item Series instead scalar, so error is raised:

date_tmp = ds.loc[ds['Security Name']==x,['Date']]

Correct way is removed []:

date_tmp = ds.loc[ds['Security Name']==x,'Date']