hash-table-count (Function)

Syntax:

Arguments and Values:

hash-table—a hash table.

count—a non-negative integer.

Description:

Returns the number of entries in the hash-table. If hash-table has just been created or newly cleared (see clrhash) the entry count is 0.

Examples:

 (setq table (make-hash-table)) → #<HASH-TABLE EQL 0/120 32115135>
 (hash-table-count table) → 0
 (setf (gethash 57 table) "fifty-seven") → "fifty-seven"
 (hash-table-count table) → 1
 (dotimes (i 100) (setf (gethash i table) i)) → NIL
 (hash-table-count table) → 100

Affected By:

clrhash, remhash, setf of gethash

See Also:

hash-table-size

Notes:

The following relationships are functionally correct, although in practice using hash-table-count is probably much faster:

 (hash-table-count table) ≡
 (loop for value being the hash-values of table count t) ≡
 (let ((total 0))
   (maphash #'(lambda (key value)
                (declare (ignore key value))
                (incf total))
            table)
   total)