DevTut

# Extracting and Listing Files in Compressed Archives

# Extracting files from a .zip archive

Unzipping a zip archive is done with unzip function from the utils package (which is included in base R).

unzip(zipfile = "bar.zip", exdir = "./foo")

This will extract all files in "bar.zip" to the "foo" directory, which will be created if necessary. Tilde expansion is done automatically from your working directory. Alternatively, you can pass the whole path name to the zipfile.

# Listing files in a .zip archive

Listing files in a zip archive is done with unzip function from the utils package (which is included in base R).

unzip(zipfile = "bar.zip", list = TRUE)

This will list all files in "bar.zip" and extract none. Tilde expansion is done automatically from your working directory. Alternatively, you can pass the whole path name to the zipfile.

# Listing files in a .tar archive

Listing files in a tar archive is done with untar function from the utils package (which is included in base R).

untar(zipfile = "bar.tar", list = TRUE)

This will list all files in "bar.tar" and extract none. Tilde expansion is done automatically from your working directory. Alternatively, you can pass the whole path name to the tarfile.

# Extracting files from a .tar archive

Extracting files from a tar archive is done with untar function from the utils package (which is included in base R).

untar(tarfile = "bar.tar", exdir = "./foo")

This will extract all files in "bar.tar" to the "foo" directory, which will be created if necessary. Tilde expansion is done automatically from your working directory. Alternatively, you can pass the whole path name to the tarfile.

# Extract all .zip archives in a directory

With a simple for loop, all zip archives in a directory can be extracted.

for (i in dir(pattern=".zip$"))
    unzip(i)

The dir function produces a character vector of the names of the files in a directory matching the regex pattern specified by pattern. This vector is looped through with index i, using the unzip function to extract each zip archive.

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