通过Common Lisp中的列表中的值删除重复项

作者: 不见你
发布时间: 2024-06-16 06:16:41 (23天前)
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那月静好 | 2019-08-31 10-32

<div class =“post-text”itemprop =“text”> <P> 这是两个hacky解决方案。 </p> <pre> <code> (defun remove-duplicates-by-name (l to-remove) ;; low performance with large to-remove lists but fine with short ;; ones (loop for e in l unless (assoc (car e) to-remove) collect e)) (defun remove-duplicates-by-name (l to-remove) ;; high performance with large to-remove lists but consy and ;; probably slow with short ones (loop with dups = (loop with dt = (make-hash-table) for e in to-remove do (setf (gethash (car e) dt) t) finally (return dt)) for e in l unless (gethash (car e) dups) collect e)) </code> </pre> </DIV>

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夏花 | 2019-08-31 10-32

<div class =“post-text”itemprop =“text”> <P> 你的例子与之无关 <EM> 重复 </EM> ，但一切都要做同 <a href="http://clhs.lisp.se/Body/14_abb.htm" rel="nofollow noreferrer"> 列表集 </A> 。 </p> <P> 例如。： </p> <pre> <code> (set-difference '((Oliver 1) (Charlie 2) (Oscar 20)) '((Oliver 2)(Charlie 3)) :key #'car) ==> ((Oscar 20)) (set-difference '((Oliver 1)) '((Oliver 2)(Charlie 3)) :key #'car) ==> () (set-difference '() '((Oliver 2)(Charlie 3)) :key #'car) ==> () </code> </pre> </DIV>

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