(time expr)
Evaluates expr and prints the time it took. Returns the value of expr.
user> (time (Thread/sleep 100))
"Elapsed time: 100.284772 msecs"
nil
;when working with lazy seqs
(time (doall (...)))
;; Time how long it takes to write a string to a file 100 times
(defn time-test []
(with-open [w (writer "test.txt" :append false)]
(dotimes [_ 100]
(.write w "I am being written to a file."))))
user=> (time (time-test))
"Elapsed time: 19.596371 msecs"
user=> (time (Thread/sleep 1000))
"Elapsed time: 1000.267483 msecs"
nil
user=> (with-out-str (time (Thread/sleep 1000)))
"\\"Elapsed time: 1010.12942 msecs\\"\
"