formatting timedelta64 when using pandas.to_excel

Question

I am writing to an excel file using an ExcelWriter:

writer = pd.ExcelWriter(fn,datetime_format=\' d  hh:mm:ss\')
df.to_excel(writer,sheet_name=\         


        

Answer 1

Some addition to the above.

Excel zero date is 1-1-1900, while pandas.TimeStamp(0) gives me 1-1-1970.

So, I changed code to

df['td_datetime'] = df['td'] + pd.Timestamp('1900-01-01')

and now it works correctly (and you can correctly add cells to add timedeltas)

Also you might like to display hours only (not 1 day 1 hour, but 25 hours) and for this you can use the following format:

writer = pd.ExcelWriter('tmp.xlsx', datetime_format='[h]:mm:ss')

Answer 2

Excel has no data type for a timedelta or equivalent, so you have a couple imperfect choices.

To keep their "datetime-ness" in Excel, you could convert to a datetime, then display them in Excel with a format showing only the time part.

df = pd.DataFrame({'td': [pd.Timedelta(1, 'h'), pd.Timedelta(1.5, 'h')]})
df['td_datetime']
df['td_datetime'] = df['td'] + pd.Timestamp(0)

writer = pd.ExcelWriter('tmp.xlsx', datetime_format='hh:mm:ss')
df.to_excel(writer)
# tmp.xlsx
# td         td_datetime
# 0.041667   01:00:00
# 0.0625     01:30:00

Alternatively, you could format as string before serializing:

df['td_str'] = df['td'].astype(str)

df
Out[24]: 
        td                     td_str
0 01:00:00  0 days 01:00:00.000000000
1 01:30:00  0 days 01:30:00.000000000