Learn Ruby
Hash
15.2
Lesson

select to select some elements of the hash

Here we have a hash of people with their house number.

Name House number
John 507
Sally 239
Adam 786
Nancy 324
Kelly 788

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. Using 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 true or false. 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.