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How to create an ID column for the combination of values in multiple columns in R data frame?
To create an ID column for the combination of values in multiple columns in R data frame, we can follow the below steps −
- First of all, create a data frame.
- Then, create an ID column using as.numeric, as.factor and with function for the combination of values in columns of the data frame.
Create the data frame
Let's create a data frame as shown below −
> x1<-rpois(20,1) > x2<-rpois(20,1) > df<-data.frame(x1,x2) > df
On executing, the above script generates the below output(this output will vary on your system due to randomization) −
x1 x2 1 0 1 2 0 1 3 0 1 4 2 2 5 4 0 6 1 0 7 3 2 8 2 0 9 0 0 10 1 0 11 0 1 12 3 1 13 2 0 14 0 1 15 0 0 16 0 1 17 1 0 18 1 4 19 0 3 20 1 0
Create an ID column for combinations
Using as.numeric function along with as.factor and with function to create an ID column for the combination of values in columns x1 and x2 −
> df$Pairs_ID<-as.numeric(as.factor(with(df,paste(x1,x2,sep="_")))) > df
Output
x1 x2 Pairs_ID 1 0 1 2 2 0 1 2 3 0 1 2 4 2 2 7 5 4 0 10 6 1 0 4 7 3 2 9 8 2 0 6 9 0 0 1 10 1 0 4 11 0 1 2 12 3 1 8 13 2 0 6 14 0 1 2 15 0 0 1 16 0 1 2 17 1 0 4 18 1 4 5 19 0 3 3 20 1 0 4
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