What is a Hash Table ?
pWhen a hash table is in use, some spots contain valid records, and other spots are "empty".
[ 0 ]
[ 1 ]
[ 2 ]
[ 3 ]
[ 4 ]
[ 5 ]
[ 700]
Number    506643548
Number    233667136
Number 281942902
Number 155778322
. . .
When a hash table is being used as a dictionary, some of the array locations are in use, and other spots are "empty", waiting for a new entry to come along.

Oftentimes, the empty spots are identified by a special key. For example, if all our identification numbers are positive, then we could use 0 as the Number that indicates an empty spot.

With this drawing, locations [0], [4], [6], and maybe some others would all have Number=0.