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bag_count(+BagHandle, -Count)

Get the number of entries in a bag
BagHandle
A bag
Count
A variable or integer

Description

This returns an integer corresponding to the number of entries currently in the bag. A fresh or erased bag has zero entries.

Modes and Determinism

Exceptions

(4) instantiation fault
BagHandle is not instantiated
(5) type error
BagHandle is not a bag
(5) type error
List is instantiated but not to an integer
(40) stale object handle
BagHandle refers to an already destroyed bag

Examples

    ?- bag_create(B), bag_count(B, N0), bag_enter(B, one), bag_count(B, N1).
    N0 = 0
    B = 'BAG'(16'0030dc48)
    N1 = 1
    Yes (0.00s cpu)
    

See Also

bag_create / 1, bag_enter / 2, bag_count / 2, bag_erase / 1, bag_abolish / 1, bag_retrieve / 2, bag_dissolve / 2