CODEWITHSUNDEEP
structlispcommon-lispmember
Rui Loureiro
Rui Loureiro

Reputation: 119

Member and structs in Lisp

I know how to check if an item is in a list: (when (member item list :test #'equalp)). If I have a list of structs book : 

(defstruct book
  name
  author
  )

how do I check if a book from a certain author is a member of the list (independently of the name)? I know this is a very beginner question and I did try to find the answer by myself but did not succeed.

Upvotes: 1

Views: 233

Answers (1)

sds
sds

Reputation: 60004

What you are looking for is :key argument:

(find author library :test #'string= :key #'book-author)

Same with member:

(member (book-name my-book) library :test #'string= :key #'book-name)

Note that :key is not called on the item.

Upvotes: 2

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