It's not possible. I see 2 options:

  1. When creating the %$hashref_isbn, also create an %incomplete_isbn which references an array containing the complete keys (or at least the parts completing the isbn)
  2. iterate through al complete isbns you have, searching for matches
s$$([},&%#}/&/]+}%&{})*;#$&&s&&$^X.($'^"%]=\&(|?*{%
+.+=%;.#_}\&"^"-+%*).}%:##%}={~=~:.")&e&&s""`$''`"e

In reply to Re: Possible to use an expression as the hash key with exists? by Skeeve
in thread Possible to use an expression as the hash key with exists? by wenD

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