在 R 中的多个 csv 文件中将唯一列分隔为多个列

Question

im trying to separate a unique column in multiple csv files. I've already done it for one single file with this code:

tempmax <- read.csv(file="path", header=TRUE, sep=";", fill = TRUE) 
colnames(tempmax) = c("Fecha", "Hora", "Temperatura max")
rbind(tempmax)
write.csv(tempmax, "path", sep = ";", append = FALSE, row.names = FALSE, col.names = FALSE)

However, I haven't found the way to do it in multiple csv saved in a folder. I would like to do the same: read, modify and write the new one.

I used this to read the multiple files:

getwd <- ("path")
filenames <- list.files("path", 
                        pattern = "*.csv", full.names = TRUE)

But i just cant find the way to edit what i want. (i'm pretty new using R) I appreciate the help. Thanks!

Answer 1

If we have several files, we can use lapply . It is not clear about the transformation. So, the file is written back by selecting the first column

lapply(filenames, function(file){
      tempmax <- read.csv(file= file, header=TRUE, sep=";", fill = TRUE) 
      colnames(tempmax) = c("Fecha", "Hora", "Temperatura max")

      write.csv(tempmax[1], file, sep = ";", append = FALSE,
             row.names = FALSE, col.names = FALSE)})