读取同一表中R中的多个文件，作为不同的变量

Question

I have 100 files, each named rundataX, where x is the number. I want to read them in in R in one table called mydata. Each of the rundata files has 3 columns: tmX , scoreX and currentX . I can read in one file like this:

mydata = read.table("rundata1", sep= " ", 
                    col.names=c("tm1","score1","current1"))

If I read in the next file, it the previous variables seem to disappear:

mydata = read.table("rundata2", sep= " ", 
                    col.names=c("tm2","score2","current2"))

Is there some option that allows me to "append" columns (and thus variables). Note that they do all have different lengths (number of rows). Most of the posts I find here are on multiple files for splitting up rows, not columns.

Answer 1

Here's way with list.files and lapply :

filenames <- list.files(pattern = "^rundata\\d+$")
dat       <- do.call(rbind, lapply(filenames, read.table, sep = " ", 
                                   col.names = c("tm", "score", "current")))

In your code, you overwrite mydata each time you use read.table .

Answer 2

If you don't mind using a loop, you can try:

file.names    <- paste("rundata", 1:100, sep= "") 
tm.names      <- paste("tm",      1:100, sep= "") 
score.names   <- paste("score",   1:100, sep= "") 
current.names <- paste("current", 1:100, sep= "") 

my.data.list <- list()
for(i in 1:100){
  my.data.list[[i]] <- read.table(file.names[i], sep= " ", 
                                  col.names=c(tm.names[i], score.names[i], 
                                              current.names[i])            )
}
my.data <- do.call(cbind, my.data.list)
rm(my.data.list, file.names, tm.names, score.names, current.names)