ToC DocOverview CGDoc RelNotes Index PermutedIndex
Allegro CL
Home Previous Up Next Table of Contents Index
  ANSI Common Lisp   18 Hash Tables   18.2 Dictionary of Hash Tables

18.2.4 hash-table-count Function

Syntax:
hash-table-count hash-table    count

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)

Allegro CL Implementation Details:
None.

Home Previous Up Next Table of Contents Index
© Franz Inc. 1998-2017 - File last updated 01-11-2017