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Problems using unique function and !duplicated

4 messages · JonC, Ivan Calandra, Claudia Beleites +1 more

Original
JonC
# 
Hi, I am trying to simultaneously remove duplicate variables from two or more
variables in a small R data.frame. I am trying to reproduce the SAS
statements from a Proc Sort with Nodupkey for those familiar with SAS. 

Here's my example data : 

test <- read.csv("test.csv", sep=",", as.is=TRUE)
date var1 var2 num1 num2
1 28/01/11    a    1  213   71
2 28/01/11    b    1  141   47
3 28/01/11    c    2  867  289
4 29/01/11    a    2  234   78
5 29/01/11    b    2  666  222
6 29/01/11    c    2  912  304
7 30/01/11    a    3  417  139
8 30/01/11    b    3  108   36
9 30/01/11    c    2  288   96

I am trying to obtain the following, where duplicates of date AND var2 are
removed from the above data.frame.

date          	var1	var2	num1	num2
28/01/2011	a	1	213	       71
28/01/2011	c	2	867	       289
29/01/2011	a	2	234	       78
30/01/2011	c	2	288	       96
30/01/2011	a	3	417	       139



If I use the !duplicated function with one variable everything works fine.
However I wish to remove duplicates of both Date and var2.

 test[!duplicated(test$date),]
        date var1 var2 num1 num2
1 0011-01-28    a    1  213   71
4 0011-01-29    a    2  234   78
7 0011-01-30    a    3  417  139

test2 <- test[!duplicated(test$date),!duplicated(test$var2),]
Error in `[.data.frame`(test, !duplicated(test$date),
!duplicated(test$var2),  :   undefined columns selected

I get an error ? 
I got different errors when using the unique() function. 

Can anybody solve this ? 

Thanks in advance.

Jon
Ivan Calandra
# 
Hi Jon,

I think you made a mistake in your desired output.
If it is indeed a mistake, then this should do:

test[!duplicated(test[,c("date","var2")]),]

HTH,
Ivan

PS: think about dput() when you want to share objects, in this case 
dput(test)


Le 2/28/2011 16:51, JonC a ?crit :

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      Claudia Beleites
    

    

      
      #
    

  


  

      
Jon,

you need to combine the conditions into one logical value, e.g. cond1 & cond2, 
e.g. !duplicated(test$date) & !duplicated(test$var2)

However, I doubt that this is what you want: you remove too many rows (rows 
whose single values appeared already, even if the combination is unique).

Have a look at the wiki, though: 
http://rwiki.sciviews.org/doku.php?id=tips:data-frames:count_and_extract_unique_rows

Claudia

        
On 02/28/2011 04:51 PM, JonC wrote:

            

      
      
      
    

        

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      (Ted Harding)
    

    

      
      #
    

  


  

      
On 28-Feb-11 15:51:17, JonC wrote:

            

      
      
      
    

        
The following gives what you state you wish to obtain (though
not quite in the same order of rows. Call the original dataframe 'df':

  df
  #       date var1 var2 num1 num2
  # 1 28/01/11    a    1  213   71
  # 2 28/01/11    b    1  141   47
  # 3 28/01/11    c    2  867  289
  # 4 29/01/11    a    2  234   78
  # 5 29/01/11    b    2  666  222
  # 6 29/01/11    c    2  912  304
  # 7 30/01/11    a    3  417  139
  # 8 30/01/11    b    3  108   36
  # 9 30/01/11    c    2  288   96

  ix <-which(duplicated(data.frame(df$date,df$var2)))
  ix
  # [1] 2 5 6 8

  df[-ix,]
  #       date var1 var2 num1 num2
  # 1 28/01/11    a    1  213   71
  # 3 28/01/11    c    2  867  289
  # 4 29/01/11    a    2  234   78
  # 7 30/01/11    a    3  417  139
  # 9 30/01/11    c    2  288   96

Does this help?
Ted.
PS I'm posting this from a temporarily subscribed alternative
address (for testing purposes) instead of my usual
ted.harding at wlandres.net

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Date: 28-Feb-11                                       Time: 16:19:59
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