R help - May 2005 - converting NA/non-NA's to a binary variable

Dear R colleagues,

I am trying to create a new column in a data frame, which converts values 
and NA's from another column into binary format. Essentially I need the 
NA's to become 1 and the rest to be 0. The code I wrote is returning the 
following error message:

Error in if (mort[i, 4] != NA) mort[i, 8] <- 0 else if (mort[i, 4] ==  :
         missing value where TRUE/FALSE needed

The code is as follows:

for(i in 1:length(mort[,4]))
	{
		if(mort[i,4] != NA) mort[i,8] <- 0
		else if(mort[i,4] == NA) mort[i,8] <- 1
	}

I'd appreciate any advice or recommendations as to a better way of 
achieving this.

Thanks
Gillian
-----------------------------------------------------------------------------------------------------
Gillian Rutherford
Eidg. Forschungsanstalt f??r Wald, Schnee und Landschaft
Swiss Federal Research Institute WSL
Economy Section, Forest Division
Z??rcherstrasse 111
CH - 8903 Birmensdorf
Phone: ++ 41 1 739 26 65
E-mail: gillian.rutherford at wsl.ch
http://www.wsl.ch/staff/gillian.rutherford/

See ?is.na

On 5/7/05, Gillian Rutherford <gillian.rutherford at wsl.ch>
wrote:
> Dear R colleagues,
> 
> I am trying to create a new column in a data frame, which converts values
> and NA's from another column into binary format. Essentially I need the
> NA's to become 1 and the rest to be 0. The code I wrote is returning
the
> following error message:
> 
> Error in if (mort[i, 4] != NA) mort[i, 8] <- 0 else if (mort[i, 4] ==  :
>         missing value where TRUE/FALSE needed
> 
> The code is as follows:
> 
> for(i in 1:length(mort[,4]))
>        {
>                if(mort[i,4] != NA) mort[i,8] <- 0
>                else if(mort[i,4] == NA) mort[i,8] <- 1
>        }
> 
> I'd appreciate any advice or recommendations as to a better way of
> achieving this.
> 
> Thanks
> Gillian
>
-----------------------------------------------------------------------------------------------------
> Gillian Rutherford
> Eidg. Forschungsanstalt f??r Wald, Schnee und Landschaft
> Swiss Federal Research Institute WSL
> Economy Section, Forest Division
> Z??rcherstrasse 111
> CH - 8903 Birmensdorf
> Phone: ++ 41 1 739 26 65
> E-mail: gillian.rutherford at wsl.ch
> http://www.wsl.ch/staff/gillian.rutherford/
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
>

mort[8] <- is.na(mort[4])

(If you really want 1/0, add  '+ 0' to this expression.)

Testing (in)equality with NA always gives NA.  This is discussed in all 
good books on S/R, e.g. in MASS (see the FAQ).

On Sat, 7 May 2005, Gillian Rutherford wrote:
> Dear R colleagues,
>
> I am trying to create a new column in a data frame, which converts values
and
> NA's from another column into binary format. Essentially I need the
NA's to
> become 1 and the rest to be 0. The code I wrote is returning the following 
> error message:
>
> Error in if (mort[i, 4] != NA) mort[i, 8] <- 0 else if (mort[i, 4] ==  :
>        missing value where TRUE/FALSE needed
>
> The code is as follows:
>
> for(i in 1:length(mort[,4]))
> 	{
> 		if(mort[i,4] != NA) mort[i,8] <- 0
> 		else if(mort[i,4] == NA) mort[i,8] <- 1
> 	}
>
> I'd appreciate any advice or recommendations as to a better way of
achieving
> this.
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

On 07-May-05 Gillian Rutherford wrote:
> Dear R colleagues,
> 
> I am trying to create a new column in a data frame, which
> converts values and NA's from another column into binary format.
> Essentially I need the NA's to become 1 and the rest to be 0.
> The code I wrote is returning the  following error message:
> 
> Error in if (mort[i, 4] != NA) mort[i, 8] <- 0 else if (mort[i, 4] == 
>:
>          missing value where TRUE/FALSE needed
> 
> The code is as follows:
> 
> for(i in 1:length(mort[,4]))
>       {
>               if(mort[i,4] != NA) mort[i,8] <- 0
>               else if(mort[i,4] == NA) mort[i,8] <- 1
>       }
> 
> I'd appreciate any advice or recommendations as to a better way of 
> achieving this.
> 
> Thanks
> Gillian
I think the following should do what you want, provided the column
mort[,8] exists:

  mort[,8] <- 0
  mort[is.na(mort[,4]),8] <- 1

Incidentally, tests like "== NA" or "!= NA" can produce
unexpected
results! Use is.na() instead:

  tmp<-NA
  ## [1] NA
  tmp==NA
  ## [1] NA
  tmp!=NA
  ## [1] NA
  if(tmp==NA) 1 else 2
  ## Error in if (tmp == NA) 1 else 2 :
  ## missing value where TRUE/FALSE needed

  if(TRUE) 1 else 2
  ## [1] 1
  is.na(tmp)
  ## [1] TRUE

  if(is.na(tmp)) 1 else 2
  ## [1] 1
  if(!is.na(tmp)) 1 else 2
  ## [1] 2

Best wishes,
Ted.


--------------------------------------------------------------------
E-Mail: (Ted Harding) <Ted.Harding at nessie.mcc.ac.uk>
Fax-to-email: +44 (0)870 094 0861
Date: 07-May-05                                       Time: 14:46:19
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