how paste function working in R? [duplicate]

问题:

This question already has an answer here:

• multiply multiple column and find sum of each column for multiple values 1 answer

this is my code

here the paste function works for only two combination.i need the same code in a loop for more than two combinations at the same time.

i<-2

while (i<=10)
 {
 results<-data.frame()
 results<- t(apply(data,1,function(x) combn(x,i,prod)))
 comb <- combn(colnames(data),i)
 colnames(results) <- apply(comb,i,function(x) paste(x[1],x[2]))
 i<-i+1
 }

now i get the two combination like

V1V2, V1V3,V1V4,....

now i want

 v1v2v3, v1v2v4, ... 

in paste function.

回答1:

comb <- combn(colnames(data),v)

colnames(results) <- apply(comb,2,function(rows) paste0(rows, collapse = ""))

insted of paste use paste0

@henrik and @chargaff