Search using hash table

Hash table can be a very efficient data structure when it comes to search operations. Since hash tables store data in an associative manner, if we know where to look for the data, we can easily get the data quickly. In the hash table, each data has a unique index associated with it. If we know which index to look at, we can find the key very easily. Usually, in other programming languages, we have to use a separate hash function to calculate the hash index to store the value. The hash function is designed to generate the same index for the same key and also avoid collision. However, one of the great features of PHP is that PHP array itself is a hash table, in its underlying C implementation. Since an array is dynamic, we do not have to worry about the size of array or overflow array with many values. We need to store the values in an associative array so...