collapse mulitple columns into one column and generate an index variable

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0

I have three date columns as shown below

       Id Date1       Date2         Date3
       12 2005-12-22  NA            NA
       11 2009-10-11  NA            NA
       29 NA          2005-04-11    NA
       45 NA          NA            2008-11-06
       39 NA          NA            2006-01-02
       44 NA          2005-04-16    NA

I am trying to collapse the three Date columns in to one Date column and create an index variable 1 if there was a Date value in Date1 column, 2 if there was a Date in Date2 column and 3 if there was a Date in Date3 column

       Id Date        Index
       12 2005-12-22  1
       11 2009-10-11  1
       29 2005-04-11  2
       45 2008-11-06  3       
       39 2006-01-02  3
       44 2005-04-16  2

I can do this using a massive ifelse statement i was wondering if anybody knew an efficient method of doing this ?

asked 22 secs ago

King Frazier

13

collapse mulitple columns into one column and generate an index variable