Here we have a hash of people with their house number.
Our task is to find all the people who live in house whose house number is more than 500.
We can use
select to do this job.
select we can get a smaller part of the original hash.
select will only select the elements for which the condition is true.
In this case the condition is that the house number should be more than 500.
It’s important to note that when
select is used then
the “do end” block should return either
If the block returns
true then that key and value pair will
be selected and if the block returns
false then that key and
value pair will be rejected.