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How to concatenate numerical columns in an R data frame?
If we have values scattered in multiple columns in an R data frame then we need to combine them and create a single column, this combining process is called concatenation. The scatteredness of the values mostly happens when the data is not well formatted to be loaded in R. Therefore, to deal with this scatteredness problem we need to use apply function.
Consider the below data frame −
Example
x1<-rpois(20,5) y1<-rpois(20,5) z1<-rpois(20,5) a1<-rpois(20,5) df1<-data.frame(x1,y1,z1,a1) df1
Output
x1 y1 z1 a1 1 3 2 1 8 2 5 2 5 8 3 9 4 1 4 4 3 4 4 4 5 5 4 4 4 6 6 5 5 3 7 5 5 5 6 8 7 3 6 4 9 5 7 6 8 10 3 3 4 5 11 7 4 4 8 12 4 3 2 4 13 6 3 6 6 14 7 5 3 1 15 6 9 8 3 16 9 6 11 6 17 5 5 6 6 18 2 4 4 9 19 1 8 2 4 20 11 4 4 2
Creating a new column in df1 by concatenating the values in all the columns of df1 −
Example
df1$all<-apply(df1,1,paste,collapse="") df1
Output
x1 y1 z1 a1 all 1 3 2 1 8 3218 2 5 2 5 8 5258 3 9 4 1 4 9414 4 3 4 4 4 3444 5 5 4 4 4 5444 6 6 5 5 3 6553 7 5 5 5 6 5556 8 7 3 6 4 7364 9 5 7 6 8 5768 10 3 3 4 5 3345 11 7 4 4 8 7448 12 4 3 2 4 4324 13 6 3 6 6 6366 14 7 5 3 1 7531 15 6 9 8 3 6983 16 9 6 11 6 96116 17 5 5 6 6 5566 18 2 4 4 9 2449 19 1 8 2 4 1824 20 11 4 4 2 11442
Example
x2<-sample(LETTERS[1:4],20,replace=TRUE) y2<-sample(LETTERS[1:4],20,replace=TRUE) z2<-sample(LETTERS[1:4],20,replace=TRUE) df2<-data.frame(x2,y2,z2) df2
Output
x2 y2 z2 1 D D C 2 D D C 3 C D A 4 D D D 5 A C B 6 A D A 7 B B D 8 B C A 9 D A C 10 A A B 11 B D D 12 A D C 13 D C C 14 C A B 15 A D A 16 A D C 17 D C A 18 A B B 19 D A C 20 D B C
Creating a new column in df2 by concatenating the values in all the columns of df2 −
Example
df2$all<-apply(df2,1,paste,collapse="") df2
Output
x2 y2 z2 all 1 D D C DDC 2 D D C DDC 3 C D A CDA 4 D D D DDD 5 A C B ACB 6 A D A ADA 7 B B D BBD 8 B C A BCA 9 D A C DAC 10 A A B AAB 11 B D D BDD 12 A D C ADC 13 D C C DCC 14 C A B CAB 15 A D A ADA 16 A D C ADC 17 D C A DCA 18 A B B ABB 19 D A C DAC 20 D B C DBC
Updated on: 06-Feb-2021
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