How to concatenate column values and create a new column in an R data frame?

Sometimes we want to combine column values of two columns to create a new column. This is mostly used when we have a unique column that maybe combined with a numerical or any other type of column. Also, we can do this by separating the column values that is going to be created with difference characters. And it can be done with the help of apply function.

Example

Consider the below data frame −

 Live Demo

> ID<-1:20
> Country<-
sample(c("Russia","USA","China","Canada","UK","India","Nepal"),20,replace=TRUE)
> df1<-data.frame(ID,Country)
> df1

Output

 ID Country
1 1 UK
2 2 UK
3 3 India
4 4 USA
5 5 USA
6 6 UK
7 7 Nepal
8 8 Russia
9 9 Nepal
10 10 China
11 11 UK
12 12 Nepal
13 13 Canada
14 14 USA
15 15 Russia
16 16 UK
17 17 China
18 18 USA
19 19 China
20 20 Russia

Creating a new column of ID and Country −

> df1$ID_with_Country<-apply(df1,1,paste,collapse="")
> df1

Output

 ID Country ID_with_Country
1 1    UK       1UK
2 2    UK       2UK
3 3   India    3India
4 4    USA     4USA
5 5   USA       5USA
6 6    UK       6UK
7 7    Nepal  7Nepal
8 8   Russia  8Russia
9 9   Nepal    9Nepal
10 10 China    10China
11 11  UK       11UK
12 12 Nepal    12Nepal
13 13 Canada 13Canada
14 14  USA    14USA
15 15 Russia    15Russia
16 16  UK       16UK
17 17 China    17China
18 18 USA       18USA
19 19 China    19China
20 20 Russia    20Russia

Let’s have a look at another example −

Example

 Live Demo

> Class<-LETTERS[1:20]
> Rank<-sample(1:10,20,replace=TRUE)
> df2<-data.frame(Class,Rank)
> df2

Output

 Class Rank
1 A    2
2 B    4
3 C    4
4 D    6
5 E    7
6 F    10
7 G    10
8 H    5
9 I    9
10 J   6
11 K   1
12 L    8
13 M    10
14 N    7
15 O    5
16 P    7
17 Q    6
18 R    1
19 S    10
20 T    3

> df2$Class_Rank<-apply(df2,1,paste,collapse="_")
> df2

Output

 Class Rank Class_Rank
1    A 2       A_ 2
2    B 4       B_ 4
3    C 4       C_ 4
4    D 6       D_ 6
5    E 7       E_ 7
6    F 10      F_10
7    G 10       G_10
8    H 5       H_ 5
9    I 9       I_ 9
10    J 6       J_ 6
11    K 1       K_ 1
12    L 8       L_ 8
13    M 10       M_10
14    N 7       N_ 7
15    O 5       O_ 5
16    P 7       P_ 7
17    Q 6       Q_ 6
18    R 1       R_ 1
19    S 10       S_10
20    T 3       T_ 3