I have several files (20) with the same column structure but with different rows structure. All are composed of two columns, the first are factors and the second are integers. I want to sum the column of integers for the factors that are repeated and the new ones that are simply added. How could I combine and sum the ones already repeated?
I've thought about combining cbind and tapply but I really do not know how to carry this out.
A simple example of the structure of the files:
Shop Clients Shop Clients Shop Clients
A 9 D 8 A 5
B 7 A 4 R 4
C 4 F 3 C 3
D 2 B 1 B 2
I expect the output:
Shop Clients
A 18
B 10
C 7
D 10
F 3
R 4
I read the different files in a loop, creating a dataset for each of them, so that the dataset shows City1$Shop and City1$Clients for example. This case is only for 20 files but I would like to know how to work with more (for example 100). How could I solve this problem by reading the datasets in this way?
f<-function(x){
read.delim2("p01.txt",header=T,sep="\t",stringsAsFactors = FALSE)
}
for(i in x){
total<-f(i)
#Here I suppose I would combine and sum the datasets
}