如果找到匹配项，则返回一行文本

Question

我在研究如何返回一行文本时遇到了一些麻烦，如果找到匹配项。

(set 'wireshark "http://anonsvn.wireshark.org/wireshark/trunk/manuf")
(set 'arptable (map (fn (x) (parse x " ")) (exec "arp -a")))
(define (cleanIPaddress x)
  (slice x 1 -1))
(define (cleanMACaddress x) 
  (upper-case (join (slice (parse x ":") 0 3) ":")))
(define (addIPandMACaddress x) 
  (list (cleanIPaddress (nth 1 x)) (cleanMACaddress (nth 3 x))))
(set 'arplist (map addIPandMACaddress arptable))
(set 'routerMAC (last (assoc (exec "ipconfig getoption en1 router") arplist)))
(find-all routerMAC (get-url wireshark))

返回

("20:AA:4B")

所以我知道代码"有效"

但我想检索整行文本

"20:AA:4B Cisco-Li # Cisco-Linksys, LLC"

Answer 1

这可以

简单地通过使用一个string-split过程来执行，该过程允许我们使用remove-if（filter的通用Lisp版本）来搜索由换行符分割的字符串，删除任何不包含我们正在搜索的字符串的行。这将导致包含字符串的每一行的列表。我们在这里定义的函数已经可以通过各种 Common Lisp 库获得，但出于教育目的，我们将自己定义它们。您需要的代码是这样的：

; First we need a function to split a string by character
(defun string-split (split-string string)
  (loop with l = (length split-string)
        for n = 0 then (+ pos l)
        for pos = (search split-string string :start2 n)
        if pos collect (subseq string n pos)
        else collect (subseq string n)
        while pos))
; Now we will make a function based on string-split to split by newlines
(defun newline-split (string)
  (string-split "
" string))
; Finally, we go through our text searching for lines that match our string.
; Make sure to replace 'needle' with the string you wish to search for.
(remove-if #'(lambda (x) 
               (equal 'nil (search (string-upcase "needle") 
                                   (string-upcase x))))
           (newline-split haystack))

您应该能够通过一些小的修改将此策略应用于您发布的代码。此代码在 Mac OS X 10.7.5 上的 SBCL 1.0.55.0-abb03f9（ANSI Common Lisp 的实现）上进行了测试。

Answer 2

最后我使用了：

(find-all (string routerMAC ".*") (get-url wireshark))