clojure File Operations Overview
Example
Read a file all at once (not recommended for large files):
(slurp "./small_file.txt")
Write data to a file all at once:
(spit "./file.txt" "Ocelots are Awesome!") ; overwrite existing content
(spit "./log.txt" "2016-07-26 New entry." :append true)
Read a file line-by-line:
(use 'clojure.java.io)
(with-open [rdr (reader "./file.txt")]
(line-seq rdr) ; returns lazy-seq
) ; with-open macro calls (.close rdr)
Write a file line-by-line:
(use 'clojure.java.io)
(with-open [wrtr (writer "./log.txt" :append true)]
(.write wrtr "2016-07-26 New entry.")
) ; with-open macro calls (.close wrtr)
Write to a file, replacing existing content:
(use 'clojure.java.io)
(with-open [wrtr (writer "./file.txt")]
(.write wrtr "Everything in file.txt has been replaced with this text.")
) ; with-open macro calls (.close wrtr)
Notes:
- You can specify URLs as well as files
- Options to
(slurp)and(spit)are passed toclojure.java.io/readerand/writer, respectively.
