[R] Excel

David Scott d.scott at auckland.ac.nz
Tue Aug 28 04:11:18 CEST 2007

A common process when data is obtained in an Excel spreadsheet is to save 
the spreadsheet as a .csv file then read it into R. Experienced users 
might have learned to be wary of dates (as I have) but possibly have not 
experienced what just happened to me. I thought I might just share it with 
r-help as a cautionary tale.

I received an Excel file giving patient details. Each patient had an ID 
code in the form of three letters followed by four digits. (Actually a New 
Zealand National Health Identification.) I saved the .xls file as .csv. 
Then I opened up the .csv (with Excel) to look at it. In the column of ID 
codes I saw: Aug-99. Clicking on that entry it showed 1/08/2699.

In a column of character data, Excel had interpreted AUG2699 as a date.

The .csv did not actually have a date in that cell, but if I had saved the 
.csv file it would have.

David Scott

David Scott	Department of Statistics, Tamaki Campus
 		The University of Auckland, PB 92019
 		Auckland 1142,    NEW ZEALAND
Phone: +64 9 373 7599 ext 86830		Fax: +64 9 373 7000
Email:	d.scott at auckland.ac.nz

Graduate Officer, Department of Statistics
Director of Consulting, Department of Statistics

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