[R] How to delete Identical columns

[David Winsemius]

On Mar 28, 2013, at 1:39 AM, Katherine Gobin wrote:

> Dear R forum
> 
> Suppose I have a data.frame 
> 
> df = data.frame(id = c(1:6), x = c(15, 21, 14, 21, 14, 38), y = c(36, 38, 55, 11, 5, 18), x.1 = c(15, 21, 14, 21, 14, 38), z = c("D", "B", "A", "F", "H", "P"))
> 
> 
>> df
>   id  x  y    x.1 z
> 1  1 15 36  15 D
> 2  2 21 38  21 B
> 3  3 14 55  14 A
> 4  4 21 11  21 F
> 5  5 14  5  14 H
> 6  6 38 18  38 P
> 
> 
> Clearly columns x and x.1 are identical. In reality, I have a large data.frame and can't make out which columns are identical, but I am sure that column with name say x is repeated as x.1, x.2 etc.
> 
> How to automatically identify and retain only one column (in this example column x) among the identical columns besides other non-identical columns (viz. id, y and z).
> 

> df[!duplicated(as.list(df))]
  id  x  y z
1  1 15 36 D
2  2 21 38 B
3  3 14 55 A
4  4 21 11 F
5  5 14  5 H
6  6 38 18 P

> 


> Regards
> 
> Katherine
> 
> 	[[alternative HTML version deleted]]
> 
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David Winsemius
Alameda, CA, USA