How to include NA in ifelse

Question

I am trying to create a column ID based on logical statements for values of other columns  For example  in the following dataframe  test  lt - structure list time   c 10L  20L  NA  30L   type   structure c 1L   2L  3L  NA    Label   c  A    B    C    class    factor    ID   c NA    1   NA  NA     Names   c  time    type    ID    row names   c NA   -4L   class    data frame     which looks like      time    type 1   10      A 2   20      B 3   NA      C 4   30      NA   I want to make a new column ID containing a value of 1 for all time that are not NA and all type that are not A  I am using the following code for this   test ID  lt - ifelse is na test time    test type     A   NA   1     This gives the result as       time    type    ID 1   10      A       NA 2   20      B       1 3   NA      C       NA 4   30      NA      NA   However  this code ignores the NA in column type  resulting in a value of NA in column ID  I need this to be a value of 1  so my needed solution should give       time    type    ID 1   10      A       NA 2   20      B       1 3   NA      C       NA 4   30      NA      1   Can anyone tell me how I might do this  I could get this to work with my existing code if I could somehow change the result of is na test type  to return FALSE instead of TRUE  but I m not sure how to do that  Or  maybe the structure of my existing code needs to be entirely changed   I appreciate any help

User · Accepted Answer

You can t really compare NA with another value  so using    would not work  Consider the following   NA    NA    1  NA   You can just change your comparison from    to  in    ifelse is na test time    test type  in   A   NA   1      1  NA   1  NA   1      Regarding your other question       I could get this to work with my existing code if I could somehow change the result of is na test type  to return FALSE instead of TRUE  but I m not sure how to do that    just use   to negate the results    is na test time     1   TRUE  TRUE FALSE  TRUE

User · Answer

You might also try an elseif   x  lt - 1 if  x   1       print  same     else if  x  gt  1       print  bigger     else       print  smaller

User · Answer

AnandaMahto has addressed why you re getting these results and provided the clearest way to get what you want  But another option would be to use identical instead of      test ID  lt - ifelse is na test time    sapply as character test type   identical   A    NA   1     Or use isTRUE   test ID  lt - ifelse is na test time    Vectorize isTRUE  test type     A    NA   1

User · Answer

It sounds like you want the ifelse statement to interpret NA values as FALSE instead of NA in the comparison  I use the following functions to handle this situation so I don t have to continuously handle the NA situation   falseifNA  lt - function x     ifelse is na x   FALSE  x     ifelse2  lt - function x  a  b     ifelse falseifNA x   a  b      You could also combine these functions into one to be more efficient  So to return the result you want  you could use   test ID  lt - ifelse2 is na test time    test type     A   NA   1

User · Answer

So  I hear this works   Data X1 lt -as character Data X1  Data GEOID lt -as character Data BLKIDFP00  Data lt -within Data X1 lt -ifelse is na Data X1  GEOID Data X2      But I admit I have only intermittent luck with it

[r] How to include NA in ifelse?

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