Creat directories
dir.create("test")
Get working wirectory
getwd()
[1] "E:/360yunpanGmail/study/R/Rmarkdown"
Set working directory
setwd("./test")
getwd()
[1] "E:/360yunpanGmail/study/R/Rmarkdown/test"
Create file
creates files with the given names if they do not already exist and truncates them if they do.
file.create("test.csv")
[1] TRUE
file.create("test1.csv", "test2.csv")
[1] TRUE TRUE
Output data to file
cat("Hello world\n", file = "test1.csv")
cat("Hello R\n", file = "test2.csv")
data(iris)
write.table(iris, file = "test.csv", row.names = FALSE, sep = ",")
Test whether file exists
file.exists("test.csv")
[1] TRUE
Read data from file
mydata1 = read.table("test.csv", header = TRUE, sep = ",")
head(mydata1)
Sepal.Length Sepal.Width Petal.Length Petal.Width Species
1 5.1 3.5 1.4 0.2 setosa
2 4.9 3.0 1.4 0.2 setosa
3 4.7 3.2 1.3 0.2 setosa
4 4.6 3.1 1.5 0.2 setosa
5 5.0 3.6 1.4 0.2 setosa
6 5.4 3.9 1.7 0.4 setosa
or
mydata2 = read.csv("test.csv", header = TRUE)
head(mydata2)
Sepal.Length Sepal.Width Petal.Length Petal.Width Species
1 5.1 3.5 1.4 0.2 setosa
2 4.9 3.0 1.4 0.2 setosa
3 4.7 3.2 1.3 0.2 setosa
4 4.6 3.1 1.5 0.2 setosa
5 5.0 3.6 1.4 0.2 setosa
6 5.4 3.9 1.7 0.4 setosa
Remove file
file.remove("test2.csv")
[1] TRUE
file.exists("test2.csv")
[1] FALSE
Delete files and directories
unlink("test1.csv")
file.exists("test1.csv")
[1] FALSE
Rename file
rename “test.csv” to “test2.csv”.
file.rename("test.csv", "test2.csv")
[1] TRUE
Append file
Append “test2.csv” to “test1.csv”.
file.append("test1.csv", "test2.csv")
[1] TRUE
head(read.csv("test1.csv", header = FALSE))
V1 V2 V3 V4 V5
1 Sepal.Length Sepal.Width Petal.Length Petal.Width Species
2 5.1 3.5 1.4 0.2 setosa
3 4.9 3 1.4 0.2 setosa
4 4.7 3.2 1.3 0.2 setosa
5 4.6 3.1 1.5 0.2 setosa
6 5 3.6 1.4 0.2 setosa
Copy file
Copy “test1.csv” to “test.csv”.
file.copy("test1.csv", "test.csv")
[1] TRUE
head(read.csv("test.csv", header = FALSE))
V1 V2 V3 V4 V5
1 Sepal.Length Sepal.Width Petal.Length Petal.Width Species
2 5.1 3.5 1.4 0.2 setosa
3 4.9 3 1.4 0.2 setosa
4 4.7 3.2 1.3 0.2 setosa
5 4.6 3.1 1.5 0.2 setosa
6 5 3.6 1.4 0.2 setosa
Extract file information
file.info("test.csv")
size isdir mode mtime ctime
test.csv 4177 FALSE 666 2013-10-08 12:45:40 2013-10-08 12:45:05
atime exe
test.csv 2013-10-08 12:45:40 no
List the files in a directory/folder
list.files(path = ".", pattern = "*.csv")
[1] "test.csv" "test1.csv" "test2.csv"
list.dirs(".")
[1] "." "./test"
Sys.glob("*.csv")
[1] "test.csv" "test1.csv" "test2.csv"
Construct path to file
file.path("test.csv")
[1] "test.csv"
Directory and file name
basename(file.path("test.csv"))
[1] "test.csv"
dirname(file.path("test.csv"))
[1] "."