Hash tables

- [Instructor] The last data structure…we'll examine is the hash table.…Some languages call these dictionaries,…but for the sake of consistency, I'll use…the term hash table in this course.…A hash table is a form of what's…called an associative array.…It's a data structure that maps keys…to their associated values, and it does this…using what's called a hash function.…This function uses the key to compute an index…into the slots that are in the hash table…and map the key to the value.…

Now, ideally, the hash function will assign…each key to a unique slot in the table…where the values are stored.…In reality, sometimes there are collisions…in which two separate keys each map…to the same slot in the table.…And in that case, the hash table has to have a way…of resolving those collisions so that…the correct value is mapped to the right key.…Now that's a bit of a complex subject,…so I'm not going to go into how hash functions work…and how collisions are resolved.…

Most languages and frameworks already have…hash table data structures that have…