xlrd “year is out of range” error, xldate_as_tuple

Question

I am trying to use the xldate_as_tuplefunction to covert a datetime and a time value from two seperate cells in a spreadsheet into python datetime and time. I intend to combine the currently seperate values into one python datetime value for use later in my code.

I can get the date row values to convert but having trouble with the time fields. I think its down to the format of the time cell in excel.

In my situation the time fields in the spreadsheet are in the following format: 00/01/1900 16:47, or 00/01/1900 17:06. All I am interested in is the time (i.e. not the 00/01/1900 bit). Thinking about it, the '00' bit of the date is not a valid day of the month so I think thats what is calusing my problems.

Thoughts appreciated as how best to get the time value. If thexldate_as_tuplewill just not work for my situation then should I consider somehow getting the value in the cell as text and parsing it...

Cheers

Answer 1

xldate_as_tuple works as advertised, producing a (year, month, day, hour, minute, second) tuple. The problem is with what you are doing with that tuple, which in your case will have 0 for each of year, month, and day.

Short answer:

If you want a time value, call datetime.time, not datetime.datetime.

Long answer:

Open Excel. Into cell A1, type 16:47:00. Copy that into B1 and C1. Format B1 with custom format yyyy-mm-dd hh:mm:ss. You should see 1900-01-00 16:47:00. Into cell D1 type =(16+47/60)/24, then format C1 and D1 as number with 8 decimal places. You should see 0.699305556 in both C1 and D1.

Fire up xlrd and try out xlrd.xldate_as_tuple:

>>> import xlrd
>>> b = xlrd.open_workbook('xlrd_time.xls')
>>> s = b.sheet_by_index(0)
>>> s.row_values(0)
[0.6993055555555556, 0.6993055555555556, 0.6993055555555556, 0.6993055555555556]
>>> [xlrd.xldate_as_tuple(t, 0) for t in s.row_values(0)]
[(0, 0, 0, 16, 47, 0), (0, 0, 0, 16, 47, 0), (0, 0, 0, 16, 47, 0), (0, 0, 0, 16, 47, 0)]
>>>

Getting your fraction-of-a-day into datetime module territory: Your data is either a time-of-day or a duration ("timedelta"), so:

>>> import datetime
>>> t = (16 + 47/60.) / 24
>>> t
0.6993055555555556
>>> datetime.timedelta(days=t)
datetime.timedelta(0, 60420)
>>> x = xlrd.xldate_as_tuple(t, 0)
>>> x
(0, 0, 0, 16, 47, 0)
>>> datetime.time(*x[3:])
datetime.time(16, 47)

Your data is not a "datetime"; attempting to make a datetime will fail as you have found out:

>>> datetime.datetime(*x)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: year is out of range