1 + 2 + 3 + ... + 10000000 时间对比：
(setq numbers (number-sequence 1 (expt 10 7)))
(chart-bar-quickie
'vertical
"Apply v.s. Reduce"
'("Apply" "Loop" "seq-reduce" "cl-reduce") "Method"
(mapcar
#'car
(list (benchmark-run (apply #'+ numbers))
(benchmark-run-compiled (cl-loop for i in numbers
sum i))
(benchmark-run (seq-reduce #'+ numbers 0))
(benchmark-run (cl-reduce #'+ numbers))))
"Seconds")
(benchmark-run (apply #'+ numbers))
;; => (0.155604 0 0.0)
(benchmark-run-compiled
(cl-loop for i in numbers
sum i))
;; => (0.316804 0 0.0)
(benchmark-run 1 (seq-reduce #'+ numbers 0))
;; => (1.328944 0 0.0)
(benchmark-run (cl-reduce #'+ numbers))
;; => (1.814373 1 0.4932320000000061)
启发自：
8 个赞
cireu
3
于是我加上-reduce又测了一次
(let ((numbers (number-sequence 1 (expt 10 7))))
(chart-bar-quickie
'vertical
"Apply v.s. Reduce"
'("Apply" "Loop" "seq-reduce" "cl-reduce" "-reduce") "Method"
(mapcar
#'car
(list (benchmark-run (apply #'+ numbers))
(benchmark-run-compiled (cl-loop for i in numbers
sum i))
(benchmark-run (seq-reduce #'+ numbers 0))
(benchmark-run (cl-reduce #'+ numbers))
(benchmark-run (-reduce #'+ numbers))))
"Seconds"))
结果不意外。
apply 调用了一次，reduce 调用了 (1- (length numbers)) 次：
(apply '+ '(1 2 3))
;; => (+ 1 2 3)
(-reduce '+ '(1 2 3))
;; => (+ (+ 1 2) 3)
reduce 在这个测试中是比较吃亏的，+ 函数没有体现 reduce 的意义：
(-reduce (lambda (acc n)
(+ acc n))
'(1 2 3))
1 个赞
ksqsf
5
chart 在 elisp 手册里都没有，究竟是怎么发现这个东西的……
这里？
这个博客有一篇关于 rx 的文章在［实用技巧］Emacs Lisp生成正则表达式 有提到：
3 个赞
这个博客的代码高亮有点厉害，还带rainbow-delimeters-mode
感谢分享，很赞的博客。