How to use grep in Ruby

In this section, we are going to learn more about a powerful method in Ruby called grep. This method is used to easily search through arrays and other collections.

We are going to learn the use of this method in a real-world Rails application.

If I go to the root of the application in the Terminal, I can run the rake routes command to get a list of all the routes in the application.

This will display all the different routes in the application, as follows:

This is helpful but also a bit overwhelming. What if I wanted only the routes specific to posts? So to filter this list, I can use the grep method. Just run the following command in the Terminal:

rake routes | grep posts

The output will be much more manageable:

When you use this command, it only brings up all the routes that have the word posts in them.

So what does grep do exactly?

Let's see a simple example:

arr = [1, 3, 2, 12, 1, 2, 3]
p arr.grep(1) 

In this code, we have a basic array of integers. From here, we call the...