[LISP]请教各位subst

lzy9788

(setq dim_sc_new 1.5)
(setq dim_sc_old (cdr (assoc 1040 (cdadr (assoc -3 ent)))) )
我想用subst和entmod来实现dim_sc_new替换dim_sc_old，
请教各位大侠怎么做

mkhsj928

ent表也太深了吧！ 首先你第二句中的cdr应改成cadr，因为cdr取得的是一个表，而根据你的意思dim_sc_old与dim_sc_new对应，所以dim_sc_old也应是一个数值而不是表 具体实现参看下面函数，也许方法显得笨了点，但能通过，企盼高人指点！ (defun mode_ent( ent / dim_sc_old dim_sc_new dim_sc_b)
(setq dim_sc_new 1.5)
(setq dim_sc_old (cadr (assoc 1040 (cdadr (assoc -3 ent)))))
(setq dim_sc_b (assoc 1040 (cdadr (assoc -3 ent))))
(setq dim_sc_new (subst dim_sc_new dim_sc_old dim_sc_b))
(setq dim_sc_old dim_sc_b)
(setq dim_sc_b (cadr (assoc -3 ent)))
(setq dim_sc_new (subst dim_sc_new dim_sc_old dim_sc_b))
(setq dim_sc_old dim_sc_b)
(setq dim_sc_b (assoc -3 ent))
(setq dim_sc_new (subst dim_sc_new dim_sc_old dim_sc_b))
(setq dim_sc_old dim_sc_b)
(setq dim_sc_b ent)
(setq dim_sc_new (subst dim_sc_new dim_sc_old dim_sc_b))
(entmod dim_sc_new)
) ent输入： ((1 2) (-3 ((1 2) (1040 2.5) (1 2)) (1 2))) 函数返回：((1 2) (-3 ((1 2) (1040 1.5) (1 2)) (1 2)))
说明通过！ 这只是测试函数的正确性，根据你的意思，ent应该是一个用（entget）函数取得 的实体数据表

无痕

(setq lst '((1 2) (-3 ((1 2) (1040 2.5) (1 2)) (1 2))))
(setq new 555)
(mapcar '(lambda (x / a b)
(setq a (car x)
b (cadr x))
(if (= a -3)
(list -3 (subst (cons 1040 new) (assoc 1040 b) b))
x
)
)lst
)
->((1 2) (-3 ((1 2) (1040 . 555) (1 2))))

mkhsj928

楼上的果然高！

lzy9788

多谢两位!