[R] Split column

[David Winsemius]

On Nov 24, 2009, at 12:53 PM, Adaikalavan wrote:

> Not very elegant but this does the trick:
>
> df <- cbind( var1=c(1,3,2,1,2), var2=c(3,1,1,2,3) )

df <- data.frame(id=1:5, df)

data.frame(id=df$id,
            var1.1 = (df$var1<3) + 2*(df$var1==3),  # 1 for < 3;  2  
for 3
             var1.2 = (df$var1==1) + 2*(df$var1>=2), # 1 for =1;   2  
otherwise
               var2.1 = (df$var2<3) + 2*(df$var2==3),  # lather, rinse,
                var2.2 = (df$var2==1) + 2*(df$var2>=2) ) # repeat

Offered not for its superior readability, since in that respect it is  
inferior to Ramasamy's solution below, but rather for possibility that  
it may run faster.

-- 
David

>
> out <- df
> out[ which(df==1, arr.ind=T) ] <- "1&1"
> out[ which(df==2, arr.ind=T) ] <- "1&2"
> out[ which(df==3, arr.ind=T) ] <- "2&2"
>
> outlist <- apply(out, 2, strsplit, split="&")
> do.call( "cbind.data.frame", lapply( outlist, do.call,  
> what="rbind" ) )
>  var1.1 var1.2 var2.1 var2.2
> 1      1      1      2      2
> 2      2      2      1      1
> 3      1      2      1      1
> 4      1      1      1      2
> 5      1      2      2      2
>
> Please check.
>
> Regards, Adai
>
>
>
> Lisaj wrote:
>> Hello, R users,
>> I have a dataset that looks like this: id   var1   var2    1       
>> 1      3    2      3      1    3      2      1    4      1       
>> 2    5      2      3   I want to split one column to two columns  
>> with 1 = 1 and 1, 2 = 1 and 2, 3 =
>> 2 and 2: id   var1.1  var1.2  var2.1  var2.2 1         1        
>> 1       2       2 2         2       2       1       1
>> 3         1       2       1       1
>> 4         1       1       1       2
>> 5         1       2       2       2
>> Can anyone please help how to get this done? Thanks a lot in advance
>> Lisa
>>
>
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David Winsemius, MD
Heritage Laboratories
West Hartford, CT