arrays - split-sequence- 用双空格分隔序列

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)))))

但是如何用双空格分隔序列呢？通常平面文件有由双空格分隔的列。

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

返回

("1  2  3  4") ;
10

此外，

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

返回

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

Answer 1

试试这个:

(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)