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Undefined operator '-' for input arguments of type 'cell'.

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Vijay
Vijay on 14 Sep 2020
Commented: Vijay on 17 Sep 2020
Hello,
I am trying to subtract two columns (that are in time domain) in spread sheet and create a new column. I attached the .xlsx file for your reference.
T = readtable('T.xlsx');
T.Time=T.BIRTHDT-T.INFODT;
But I am getting an error message: Undefined operator '-' for input arguments of type 'cell'.
I presume either the format of the two columbs might be different or one column is missing the hours/min/seconds information. But not sure how to sort.
Any help would be highly appreciated.

Accepted Answer

Star Strider
Star Strider on 15 Sep 2020
Try this:
T = readtable('FindDifference.xlsx');
T.INFODT = datetime(T.INFODT);
T.BIRTHDT = datetime(T.BIRTHDT);
T.Time = years(T.BIRTHDT-T.INFODT);
This puts ‘T.Time’ in units of years. Other units are possible. See the documentation for more information.
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More Answers (1)

Walter Roberson
Walter Roberson on 15 Sep 2020
filename = 'FindDifference.xlsx';
opt = detectImportOptions(filename);
opt = setvaropts(opt, {'BIRTHDT', 'INFODT'}, 'Type', 'datetime');
T.Time=T.BIRTHDT-T.INFODT;
T.Format = 'y';
However, I think you will be rather startled at the results.
The INFODT column has hard-coded into it years such as 0011 . This is not just a mistake of interpretation of numeric values: the column is a text column, not a date column or a numeric column (I checked in Excel.) If someone deliberately wanted to code in year 11 CE then that is probably how they would code it.
I would suggest that probably before doing the subtraction, you should have
T.INFODT = T.INFODT + calyears(1900);
  3 Comments
Vijay
Vijay on 15 Sep 2020
I have been using 2019b (Windows) which resulted in the format below.
3000 '01-Apr-0016 00:00:00' 0 '01-Jan-1959'
3000 '01-Feb-0011 00:00:00' 0 '01-Jan-1945'
3000 '01-Feb-0013 00:00:00' 0 '01-Jan-1948'
3000 '01-Feb-0018 00:00:00' 0 '01-Jan-1954'
Now, when I tried with 2020a the format became...
3000 'Feb-0011' 0 01-Jan-1941
3000 'Mar-0012' 0 01-Jan-1941
3000 'Feb-0013' 0 01-Jan-1941
3000 'Mar-0014' 0 01-Jan-1941
Not sure why the year is taken as 0011 instead of 2011.
In any case, still I can't subtract the column values.

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