Question

我知道如何用空格分隔字符串序列：

(defun ff-cols (dir file)
  (with-open-file (ff-cols-str pathname :direction :input)
    (length (split-sequence #\Space (read-line ff-cols-str nil 'eof)))))

但是如何用双空格界定序列呢？通常是平面文件由双空格分隔的列。

(split-sequence "  " "1  2  3  4")

返回

("1  2  3  4") ;
10

另外，

(split-sequence #\Space "1  2  3  4")

返回

("1" "" "2" "" "3" "" "4") ;
10

Answer 1

请改为尝试：

(split-sequence-if (lambda (s) (equal s "  ")) "1  2  3  4")

或者这个：

(split-sequence #\Space "1  2  3  4" :remove-empty-subseqs t)

Answer 2

(ql:quickload "cl-ppcre")
(cl-ppcre:split "\\s\\s" "One  Two Three  Four   Five")
("One" "Two Three" "Four" " Five")

显然，无论你从其他使用正则表达式的语言中学到什么都适用。

Answer 3

这可能是因为你的字符串没有用空格分隔

(split-sequence "  " "1 2 3 4")

试

(split-sequence "  " "1  2  3  4")

双空间分裂序列 - 分隔序列

3 个答案: