R: Code Execution
Theory
R is a language and environment for statistical computing and graphics. It is a GNU project which is similar to the S language and environment which was developed at Bell Laboratories (formerly AT&T, now Lucent Technologies) by John Chambers and colleagues.
Practical
System Commands
# System()
system("ls -l") # Executes the ls -l command in Unix-like systems
# System2()
output <- system2("ls", args = "-l", stdout = TRUE)
output
# Shell()
shell("ls -l")
File Reading
# read.csv()
data <- read.csv("file.csv")
# read.table()
data <- read.table("file.txt", sep = "\t", header = TRUE)
# readLines()
lines <- readLines("/etc/passwd")
# scan()
data <- scan("file.txt", what = "character", sep = ",")
# file()
con <- file("file.txt", "r")
List Directory Contents
# dir()
files <- dir()
print(files)
# file.access()
file.access(dir("/etc/"))
0: No access permissions.
1: Execute access.
2: Write access.
4: Read access.
6: Read and write access.
7: Read, write, and execute access.
REFERENCES
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