怎样提取运算符号两边的数字？

qazxswk

例如    “500/2” 或者“100*20”或者“300-100”或者“100+50”
就是这样有运算符号的字符串，提取两边的数字，两边数字长度不定。

qazxswk

我自己想到一个方案，抛砖引玉，我本想通过这个代码，引入到一些需要输入数据的插件中，如拉伸、移动、偏移。希望大家提提建议。
现在，如果输入500*2，后面结果会得到1000。

1. (defun c:tt(/ com n txt1 txt2 zhi)
   
2. (setq com (getstring "\n输入数据:"))
   
3. (if (or
   
4. (if (setq n (vl-string-search "+" com))
   
5. (progn
   
6. (setq txt1 (substr com 1 n))
   
7. (setq txt2 (substr com (+ n 2)))
   
8. (setq zhi (+ (atof txt1) (atof txt2)))
   
9. ))
   
10. (if (setq n (vl-string-search "-" com))
    
11. (progn
    
12. (setq txt1 (substr com 1 n))
    
13. (setq txt2 (substr com (+ n 2)))
    
14. (setq zhi (- (atof txt1) (atof txt2)))
    
15. ))
    
16. (if (setq n (vl-string-search "*" com))
    
17. (progn
    
18. (setq txt1 (substr com 1 n))
    
19. (setq txt2 (substr com (+ n 2)))
    
20. (setq zhi (* (atof txt1) (atof txt2)))
    
21. ))
    
22. (if (setq n (vl-string-search "/" com))
    
23. (progn
    
24. (setq txt1 (substr com 1 n))
    
25. (setq txt2 (substr com (+ n 2)))
    
26. (setq zhi (/ (atof txt1) (atof txt2)))
    
27. )))
    
28. (princ (strcat "\n运算结果为:"(rtos zhi)))
    
29. (princ (strcat "\n输入数值为:"com))
    
30. )
    
31. (princ))

(defun c:tt(/ com n txt1 txt2 zhi)<br /> (setq com (getstring "\n输入数据:"))<br /> (if (or<br /> (if (setq n (vl-string-search "+" com))<br /> (progn<br /> (setq txt1 (substr com 1 n))<br /> (setq txt2 (substr com (+ n 2)))<br /> (setq zhi (+ (atof txt1) (atof txt2)))<br /> ))<br /> (if (setq n (vl-string-search "-" com))<br /> (progn<br /> (setq txt1 (substr com 1 n))<br /> (setq txt2 (substr com (+ n 2)))<br /> (setq zhi (- (atof txt1) (atof txt2)))<br /> ))<br /> (if (setq n (vl-string-search "*" com))<br /> (progn<br /> (setq txt1 (substr com 1 n))<br /> (setq txt2 (substr com (+ n 2)))<br /> (setq zhi (* (atof txt1) (atof txt2)))<br /> ))<br /> (if (setq n (vl-string-search "/" com))<br /> (progn<br /> (setq txt1 (substr com 1 n))<br /> (setq txt2 (substr com (+ n 2)))<br /> (setq zhi (/ (atof txt1) (atof txt2)))<br /> )))<br /> (princ (strcat "\n运算结果为:"(rtos zhi)))<br /> (princ (strcat "\n输入数值为:"com))<br /> )<br /> (princ))

guosheyang

如果是为了计算值  可以这样
(arxload "geomcal")
(cal "500/2")
(cal "100*20")
(cal "300-100")
(cal "100+50")

xiang19751218

用正则表达式
;|
功能 对字符串进行正则表达式匹配测试.
参数:
pat = 正则表达式模式 ,对应vbs正则表达式的模式(expression)。说明: \\号要用\\\\替代.
str = 字符串
key = \"i\" \"g\" \"m\" , \"i\"不区分大小写（Ignorecase）,\"g\"全局匹配（Global）.
           \"m\"多行模式（Multiline），以上几个关键字可以组合使用，或用 \"\".
返回: 返回匹配的字符列表，或无一匹配返回nil

命令: (xd::string:regexps "\\d+\\.?\\d*" "100*20"  "") =>("100" "20")
命令: (xd::string:regexps "\\d+\\.?\\d*" "100.1+20"  "") =>("100.1" "20")
|;
(defun XD::String:RegExpS (pat str key / end keys matches x)
  (if (not *xxvbsexp)
    (setq *xxvbsexp (vlax-get-or-create-object "VBScript.RegExp"))
  )
  (vlax-put *xxvbsexp 'Pattern pat)
  (if (not key)
    (setq key "")
  )
  (setq key (strcase key))
  (setq keys '(("I" "IgnoreCase") ("G" "Global")
         ("M" "Multiline")
        )
  )
  (mapcar
    '(lambda (x)
       (if (wcmatch key (strcat "*" (car x) "*"))
         (vlax-put *xxvbsexp (read (cadr x)) 0)
         (vlax-put *xxvbsexp (read (cadr x)) -1)
       )
     )
    keys
  )
  (setq matches (vlax-invoke *xxvbsexp 'Execute str))
  (vlax-for x matches (setq end (cons (vla-get-value x) end)))
  (reverse end)
)

你有种再说一遍

xiang19751218 发表于 2024-6-23 22:03
用正则表达式
;|
功能 对字符串进行正则表达式匹配测试.

Dijkstra算法,使用两个栈实现四则表达式的计算
https://v.douyin.com/i6F6N9TD/