What is 4/16 in hashes?

Question

if (%hash){
     print \"That was a true value!\\n\";
}

That will be true if (and only if) the hash has at least

Answer 1

A hash is an array of linked lists. A hashing function converts the key into a number which is used as the index of the array element ("bucket") into which to store the value. More than one key can hash to the same index ("collision"), a situation handled by the linked lists.

The denominator of the fraction is the total number of buckets.

The numerator of the fraction is the number of buckets which has one or more elements.

For hashes with the same number of elements, the higher the number, the better. The one that returns 6/8 has fewer collisions than the one that returns 4/8.