[讨论]：请高手帮忙。

ssgmyvvfb

今天我做了一个雪花纷飞可不就是不成攻能帮我看一下，以下的程序到底错在那里给小弟指点？
题目：
选取两圆EN1及EN2，作两条内公切线，并将EN2圆内侧虚线剪掉，询问阵列次数NN，以EN1圆心为阵列中心点，作环形阵列。
(defun c:lsp7()
  (setvar "cmdecho" 0)
  (setq en1 (entsel "\n先取圆1:"))
  (setq en2 (entsel "\n选取圆2:"))
  (setq en1data (entget en1))
  (setq en2data (entget en2))
  (setq cen1 (assoc 10 enldata))
  (setq cen2 (assoc 10 en2data))
  (setq r1 (assoc 40 en1data))
  (setq r2 (assoc 40 en2data))
  (setq ang (angle cen1 cen2))
  (setq p1 (polar cen1 (+ ang (/ pi 2)) r1))
  (setq p2 (polar cen1 (- ang (/ pi 2)) r1))
  (setq p3 (polar cen2 (+ ang (/ pi 2)) r2))
  (setq p4 (polar cen2 (- ang (/ pi 2)) r2))
  (command "line" "tan" p1 "tan" p4 "")
  (setq en3 (entlast))
  (command "line" "tan" p2 "tan" p3 "")
  (setq en4 (entlast))
  (setq nn (getint "\n重复次数<8>:"))
  (if (null nn) (setq nn 8))
  (command "trim" en3 en4 "" (list en2 (polar cen2 ang (* -1 r2))) "")
  (command "array" en3 en4 (polar cen2 ang r2) "" "p" cen1 nn "" "")
  (prin1)
  )

zxq0220

修改后：

2. 
   
3. (defun c:lsp7()
   
4. (setvar "cmdecho" 0)
   
5. (setq en1 (entsel "\n先取圆1:"))
   
6. (setq en2 (entsel "\n选取圆2:"))
   
7. (setq en1data (entget (car en1)))
   
8. (setq en2data (entget (car en2)))
   
9. (setq cen1 (cdr (assoc 10 en1data)))
   
10. (setq cen2 (cdr (assoc 10 en2data)))
    
11. (setq r1 (cdr (assoc 40 en1data)))
    
12. (setq r2 (cdr (assoc 40 en2data)))
    
13. (setq ang (angle cen1 cen2))
    
14. (setq p1 (polar cen1 (+ ang (/ pi 2)) r1))
    
15. (setq p2 (polar cen1 (- ang (/ pi 2)) r1))
    
16. (setq p3 (polar cen2 (+ ang (/ pi 2)) r2))
    
17. (setq p4 (polar cen2 (- ang (/ pi 2)) r2))
    
18. (command "line" "tan" p1 "tan" p4 "")
    
19. (setq en3 (entlast))
    
20. (command "line" "tan" p2 "tan" p3 "")
    
21. (setq en4 (entlast))
    
22. (setq nn (getint "\n重复次数<8>:"))
    
23. (if (null nn) (setq nn 8))
    
24. (command "trim" en3 en4 "" "nea" (polar cen2 ang (* -1 r2)) "")
    
25. (command "array" en3 en4 (polar cen2 ang r2) "" "p" cen1 nn "" "")
    
26. (prin1)
    
27. )
    

<br /> (defun c:lsp7()<br /> (setvar "cmdecho" 0)<br /> (setq en1 (entsel "\n先取圆1:"))<br /> (setq en2 (entsel "\n选取圆2:"))<br /> (setq en1data (entget (car en1)))<br /> (setq en2data (entget (car en2)))<br /> (setq cen1 (cdr (assoc 10 en1data)))<br /> (setq cen2 (cdr (assoc 10 en2data)))<br /> (setq r1 (cdr (assoc 40 en1data)))<br /> (setq r2 (cdr (assoc 40 en2data)))<br /> (setq ang (angle cen1 cen2))<br /> (setq p1 (polar cen1 (+ ang (/ pi 2)) r1))<br /> (setq p2 (polar cen1 (- ang (/ pi 2)) r1))<br /> (setq p3 (polar cen2 (+ ang (/ pi 2)) r2))<br /> (setq p4 (polar cen2 (- ang (/ pi 2)) r2))<br /> (command "line" "tan" p1 "tan" p4 "")<br /> (setq en3 (entlast))<br /> (command "line" "tan" p2 "tan" p3 "")<br /> (setq en4 (entlast))<br /> (setq nn (getint "\n重复次数<8>:"))<br /> (if (null nn) (setq nn 8))<br /> (command "trim" en3 en4 "" "nea" (polar cen2 ang (* -1 r2)) "")<br /> (command "array" en3 en4 (polar cen2 ang r2) "" "p" cen1 nn "" "")<br /> (prin1)<br /> )<br />

ssgmyvvfb

这里为什么不用(setq cen1(assoc 10 en1data))) 而用 (setq cen1 (cdr (assoc 10 en1data)))  ？
还有这条1.(setq r2 (assoc 40 en2data)) 而用2.(setq r2 (cdr (assoc 40 en2data)))
1.r2求出来就是半径了  为什么还要加上一个cdr呢？
这么兄台你能帮我一下吗？

ljpnb

下面这段是任一个圆的DXF数据:
选择对象: ((-1 . <图元名: 7ef55558>) (0 . "CIRCLE") (330 . <图元名: 7ef53cc0>)
(5 . "1D3") (100 . "AcDbEntity") (67 . 0) (410 . "Model") (8 . "CONTINUOUS")
(100 . "AcDbCircle") (10 98.5853 117.008 0.0) (40 . 26.1973) (210 0.0 0.0 1.0))

用(setq cen1(assoc 10 en1data))) 取出是(10 98.5853 117.008 0.0)
用(setq cen1 (cdr (assoc 10 en1data))) 取出是(98.5853 117.008 0.0)

ssgmyvvfb

（10 98.5853 117.008 0.0)）
还有那个10是不是就是代表圆心啊

czg09180274

DXF格式中规定，每一个列表代表图形的每一个数据，为了区别和易于阅读每一组数据都用“组码和数据”进行点对，你要求的是数据就得把数据从它所属的列表中提取出来，要不取出来的是列表是不能参与你后面的运算的。

ssgmyvvfb

真的太谢谢你们了，我终于明白了，