读取R中的文件列表

Question

In R, I am trying to process multiple files using a loop. A file contains paths of many other files that contain data for computation. Can somebody tell me the simple script to do it?

list.txt:

/data/tmp/b.dat
/data/tmp/c.dat
/data/tmp/d.dat

inside b.dat:

1 15.30 20.30 15.0
2 7.3 5.0 2.0
...
n 5.0 2.0 6.0

In the meantime, data is processed for each row. How can the data be transposed?

Answer 1

Here's a one-liner:

lapply(scan("list.txt",""), read.table,sep=" ", row.names=1)

A short explanation: scan("list.txt","") scans your file containing the list of locations (space separated)and outputs them as a vector of characters (because of the "" ) then with lapply you apply to each of those locations the function read.table with the right separator and other needed arguments. The final output is a list of datasets.