R - best way to apply an if statement on multiple arguments - r

Question

Example: Let's say I have the two dataframes
DF1 = data.frame(V1 = c("","A", "B"), V2 = c("x",0,1), V3 = c("y",2,3), V4 = c("z",4,5))
DF2 = data.frame(V1 = c("","A", "B"), V2 = c("x",6,7), V3 = c("y",8,9), V4 = c("z",0,0))
so
> DF1 > DF2
V1 V2 V3 V4 V1 V2 V3 V4
1 x y z 1 x y z
2 A 0 2 4 2 A 6 8 0
3 B 1 3 5 3 B 7 9 0
and I want to have the first row as column names here, so
>DF1 > DF2
x y z x y z
1 A 0 2 4 1 A 6 8 0
2 B 1 3 5 2 B 7 9 0
What I do to achieve this is
if("V2" %in% names(DF1)){
names(DF1) = as.character(unlist(DF1[1,]))
DF1 = DF1[-1, ]
}
if("V2" %in% names(DF2)){
names(DF2) = as.character(unlist(DF2[1,]))
DF2 = DF2[-1, ]
}
which does what we want in this example.
QUESTION: What's the best way here to avoid having two if statements here? The first thing that came to my mind is iterating over the two DFs in a loop, but this doesn't work because you have to rename the DFs (at least it didn't work for me)
Or more generally, how to avoid doing the same thing for multiple arguments where loops don't work

Answer 1

We could use row_to_names from janitor
library(janitor)
DF1 <- row_to_names(DF1, 1)
DF2 <- row_to_names(Df2, 1)

Answer 2

There must be a better way but until someone gives that, I think this chunk of code works:
DF1 = data.frame(V1 = c("","A", "B"), V2 = c("x",0,1), V3 = c("y",2,3), V4 = c("z",4,5))
DF2 = data.frame(V1 = c("","A", "B"), V2 = c("x",6,7), V3 = c("y",8,9), V4 = c("z",0,0))
FUNK = function(x){
if("V2" %in% names(x)){
names(x) = as.character(unlist(x[1,]))
x = x[-1, ]
}
return(x)
}
list1 = list(DF1,DF2)
list2 = lapply(1:2,FUN = function(x) FUNK(list1[[x]]))
for (i in 1:2){
assign(paste0("DF",i),list2[[i]])
}
The function just does the if statement, then this is applied to a list of dataframes, and then the new dataframes are assignd to original names using "assign" function.

Answer 3

You can avoid using if condition at all in this problem. Is this what you desire?
ls <- list(DF1,DF2)
for (k in 1:length(ls)) {
names(ls[[k]]) <- ls[[k]] %>% slice(1) %>% unlist()
assign(paste0("DF",k),ls[[k]][-1,])
}
row.names(DF1) <- NULL
row.names(DF2) <- NULL
output
> DF1
x y z
1 A 0 2 4
2 B 1 3 5
> DF2
x y z
1 A 6 8 0
2 B 7 9 0