from long to wide format multiple variables in R - long-format-data

Question

I have a table in long format like this:
gene tissue tpm
A liver 5
A brain 2
B ovary 10
B brain 1
C brain 15
C liver 6
I'd like to convert it into a wider format:
gene tissue1 tissue2 tpm1 tpm2
A liver brain 5 2
B ovary brain 10 1
C brain liver 15 6
I have tried with dcast and spread but I get this result:
gene liver brain ovary
A 5 2 NA
B NA 1 10
C 6 15 NA
Which is NOT what I want.
Thank you!

Answer 1

I am not aware of a function that can solve this puzzle all at once in R language, but you can use a for loop to rearrange you data frame.
The code is presented below:
data <- data.frame(gene=c("A","A","B","B","C","C"),
tissue=c("liver", "brain", "ovary", "brain", "brain", "liver"),
tpm=c(5,2,10,1,15,6))
gene.unique <- unique(data$gene)
i <- 1
for (dummy in gene.unique) {
genes.idx <- which(data$gene == dummy)
tissue1[i] <- data$tissue[genes.idx[1]]
tissue2[i] <- data$tissue[genes.idx[2]]
tpm1[i] <- data$tpm[genes.idx[1]]
tpm2[i] <- data$tpm[genes.idx[2]]
i <- i+1
}
data.final <- data.frame(gene=gene.unique, tissue1, tissue2, tpm1, tpm2)
gene tissue1 tissue2 tpm1 tpm2
1 A liver brain 5 2
2 B ovary brain 10 1
3 C brain liver 15 6
I hope it helps you.