repeat；vl-remove-if；foreach；while；mapcar速度对比

;;;开发过程，图元多时对速度要求较高，特写此程序测试
;;;师兄:QQ 361865648 
;;;实验结果：vl-remove-if最快，foreach次之
;;;repeat和while每次都一样
;;;repeat表条件筛选速度测试,参考：15.75 秒
(defun c:tt1 (/ s seconds lst mylst i s2 seconds2)
  (setq s (getvar "DATE"))
  (setq seconds (* 86400.0 (- s (fix s))))
  (setq lst (ATOMS-FAMILY 1))
  (setq n(length lst) lst1 lst)
  (repeat 1000
    (setq i 0
            mylst  nil
            lst1 lst
    )
    (repeat n
      ;(setq thisitm (nth i lst)
            ;      i      (1+ i)
      ;)
      (setq thisitm (car lst1) lst1 (cdr lst1))
      (if (= "A" (substr thisitm 1 1))
                (setq mylst (cons thisitm mylst))
      )
    )
  )
    (setq mylst (REVERSE ylst));_这行对速度基本没影响
  (setq s2 (getvar "DATE"))
  (setq seconds2 (* 86400.0 (- s2 (fix s2))))
  (princ
    (strcat "\ntt1 Repeat 运行时间：" (rtos (- seconds2 seconds) 2 2) " 秒")
  )
)
;(defun c:tt1 (/ s seconds lst mylst i s2 seconds2)
;  (setq s (getvar "DATE"))
;  (setq seconds (* 86400.0 (- s (fix s))))
;  (setq lst (ATOMS-FAMILY 1))
;  (setq n(length lst))
;  (repeat 100
;    (setq i 0
;            mylst    nil
;    )
;    (repeat n
;      (setq thisitm (nth i lst)
;                i        (1+ i)
;      )
;      (if (= "A" (substr thisitm 1 1))
;                (setq mylst (cons thisitm mylst))
;      )
;    )
;  )
;    (setq mylst (REVERSE ylst));_这行对速度基本没影响
;  (setq s2 (getvar "DATE"))
;  (setq seconds2 (* 86400.0 (- s2 (fix s2))))
;  (princ
;    (strcat "\n tt1 运行时间：" (rtos (- seconds2 seconds) 2 2) " 秒")
;  )
;)
;;;vl-remove-if-not表条件筛选速度测试 参考：11.79 秒
(defun c:tt2 (/ s seconds lst mylst s2 seconds2)
  (setq s (getvar "DATE"))
  (setq seconds (* 86400.0 (- s (fix s))))
  (setq lst (ATOMS-FAMILY 1))
  (repeat 1000
    (setq mylst    (vl-remove-if
                                    '(lambda (x)
                                         (/= "A" (substr x 1 1))
                                     )
                                    lst
                                )
    )
  )
  (setq s2 (getvar "DATE"))
  (setq seconds2 (* 86400.0 (- s2 (fix s2))))
  (princ
    (strcat "\ntt2 Vl-Remove-If 运行时间：" (rtos (- seconds2 seconds) 2 2) " 秒")
  )
)
;;;foreach表条件筛选速度测试 参考：14.36 秒
(defun c:tt3 (/ s seconds lst mylst itm s2 seconds2)
  (setq s (getvar "DATE"))
  (setq seconds (* 86400.0 (- s (fix s))))
  (setq lst (ATOMS-FAMILY 1))
  (repeat 1000
    (setq mylst nil)
    (foreach itm lst
      (if (= "A" (substr itm 1 1))
                (setq mylst (cons itm mylst))
      )
    )
  )
  (setq mylst (REVERSE mylst));_这行对速度基本没影响
  (setq s2 (getvar "DATE"))
  (setq seconds2 (* 86400.0 (- s2 (fix s2))))
  (princ
    (strcat "\ntt3 Foreach 运行时间：" (rtos (- seconds2 seconds) 2 2) " 秒")
  )
)
;;;while表条件筛选速度测试，每次和tt1都一样:17.15 秒
(defun c:tt4 (/ i len s seconds lst mylst itm s2 seconds2)
  (setq s (getvar "DATE"))
  (setq seconds (* 86400.0 (- s (fix s))))
  (setq lst (ATOMS-FAMILY 1))
    (setq len(length lst) )
  (repeat 1000
    (setq mylst nil i 0 lst1 lst)
    (while (< i len)
            ;(setq itm(nth i lst))
      (setq itm (car lst1) lst1 (cdr lst1))
      (if (= "A" (substr itm 1 1))
                (setq mylst (cons itm mylst))
            )
      (setq i(1+ i))
        )
    )
  (setq mylst (REVERSE mylst));_这行对速度基本没影响
  (setq s2 (getvar "DATE"))
  (setq seconds2 (* 86400.0 (- s2 (fix s2))))
  (princ
    (strcat "\ntt4 While 运行时间：" (rtos (- seconds2 seconds) 2 2) " 秒")
  )
)
;(defun c:tt4 (/ i len s seconds lst mylst itm s2 seconds2)
;  (setq s (getvar "DATE"))
;  (setq seconds (* 86400.0 (- s (fix s))))
;  (setq lst (ATOMS-FAMILY 1))
;    (setq len(length lst) )
;  (repeat 100
;    (setq mylst nil i 0)
;        
;    (while (< i len)
;            (setq itm(nth i lst))
;      (if (= "A" (substr itm 1 1))
;                (setq mylst (cons itm mylst))
;            )
;      (setq i(1+ i))
;        )
;    )
;  (setq mylst (REVERSE mylst));_这行对速度基本没影响
;  (setq s2 (getvar "DATE"))
;  (setq seconds2 (* 86400.0 (- s2 (fix s2))))
;  (princ
;    (strcat "\ntt3 运行时间：" (rtos (- seconds2 seconds) 2 2) " 秒")
;  )
;)
;;;mapcar表条件筛选速度测试，每次和tt1都一样:11.68 秒
(defun c:tt5 (/ i len s seconds lst mylst itm s2 seconds2)
  (setq s (getvar "DATE"))
  (setq seconds (* 86400.0 (- s (fix s))))
  (setq lst (ATOMS-FAMILY 1))
    (setq len(length lst) )
  (repeat 1000
    (setq mylst nil i 0 )
        (mapcar '(lambda (itm)
                             (if (= "A" (substr itm 1 1))
                                 (setq mylst (cons itm mylst))
                             )
                         )
            lst)
    )
  (setq mylst (REVERSE mylst));_这行对速度基本没影响
  (setq s2 (getvar "DATE"))
  (setq seconds2 (* 86400.0 (- s2 (fix s2))))
  (princ
    (strcat "\ntt5 Mapcar 运行时间：" (rtos (- seconds2 seconds) 2 2) " 秒")
  )
)
(c:tt1)
(c:tt2)
(c:tt3)
(c:tt4)
(c:tt5)
(prin1)