How to add values in columns having same name and merge them in R?

To add values in columns having same name and merge them in R, we can follow the below steps −

• First of all, create a data frame.
• Add column values that have same name and merge them by using cbind with do.call.

Create the data frame

Let's create a data frame as shown below −

df<-
data.frame(x=rpois(25,1),y=rpois(25,2),x=rpois(25,5),z=rpois(25,2),y=rpois(25,1),z=rpoi
s(25,5),check.names=FALSE)
df

On executing, the above script generates the below output(this output will vary on your system due to randomization) −

  x y x z y z
1 1 1 7 1 1 1
2 3 2 4 0 3 4
3 1 3 4 2 0 3
4 1 1 9 2 3 3
5 1 2 3 0 3 8
6 1 3 2 1 0 4
7 1 2 5 2 2 4
8 0 1 6 3 2 7
9 1 4 4 2 1 1
10 1 2 3 3 0 3
11 2 2 10 1 0 14
12 2 2 2 2 0 1
13 0 3 5 3 0 6
14 2 1 3 2 0 5
15 0 2 5 6 1 4
16 1 2 3 0 0 5
17 0 2 7 2 2 11
18 3 2 4 1 2 5
19 0 7 5 1 0 10
20 0 3 3 1 0 6
21 1 1 5 7 5 6
22 1 0 5 3 2 5
23 3 3 3 3 0 2
24 2 0 6 4 1 7
25 0 7 1 2 1 4

Add column values having same name and merge them

Use do.call function with cbind function to add column values with colSums function as shown below −

df<-
data.frame(x=rpois(25,1),y=rpois(25,2),x=rpois(25,5),z=rpois(25,2),y=rpois(25,1),z=rpoi
s(25,5),check.names=FALSE)
Merged_df<-as.data.frame(do.call(cbind,
by(t(df),INDICES=names(df),FUN=colSums)))
Merged_df

Output

   x y z
V1 8 2 2
V2 7 5 4
V3 5 3 5
V4 10 4 5
V5 4 5 8
V6 3 3 5
V7 6 4 6
V8 6 3 10
V9 5 5 3
V10 4 2 6
V11 12 2 15
V12 4 2 3
V13 5 3 9
V14 5 1 7
V15 5 3 10
V16 4 2 5
V17 7 4 13
V18 7 4 6
V19 5 7 11
V20 3 3 7
V21 6 6 13
V22 6 2 8
V23 6 3 5
V24 8 1 11
V25 1 8 6