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"missings=function(x) x[x==998|x==999]<-NA" doesn't work...

3 messages · Doreen Mueller, Sarah Goslee, Ben Tupper

Original
Doreen Mueller
# 
Hi!

I want to have a function that assigns NAs to certain values of my 
variable "var" in the dataset "d". This doesn't work:
0      1  999 <NA> 
 220  752  321 5264 

I don't get any error messages, but "d$var" remains unchanged. The 
function:
doesn't work either, and I read that "<<-" is "dangerous" anyway?

It is important for me to work with variable names (and therefore with 
functions instead loops) because the number and order of variables in my 
dataset changes regularly.

Thank you,
Doreen
Sarah Goslee
# 
You need to assign the output of missings() to something. For that
matter, missings() needs some output.

d <- data.frame(a=1:5, b=6:10, var=c(1, 1, 998, 999, 2))

missings <- function(x) {
    x[x==998|x==999]<-NA
    x
}

d$var <- missings(d$var)
a  b var
1 1  6   1
2 2  7   1
3 3  8  NA
4 4  9  NA
5 5 10   2


Sarah
On Thu, Sep 18, 2014 at 10:13 AM, Doreen Mueller <Doreen.Mueller at dza.de> wrote:

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Ben Tupper
    

    

      
      #
    

  


  

      
Hi,

        
On Sep 18, 2014, at 10:13 AM, Doreen Mueller <Doreen.Mueller at dza.de> wrote:

        

            

      
      
      
    

        
You are so close.  R returns the value of the last thing evaluated in your function.  In this case, the *copy* of your input argument was modified within the function, but you didn't return the value of the copy to the calling environment.  You need to explicitly return the modified value.

            

      
      
      
    

        
[1]  990  991  992  993  994  995  996  997   NA   NA 1000 1001 1002 1003 1004 1005 1006 1007
[19] 1008 1009 1010

By the way, don't forget to switch your email client to use text instead of html when sending a message to the list.

Cheers,
Ben