Ruby has aliases for a lot of methods.
For example if you open Ruby
Enumerable
documentation and if you look at the sidebar then you will see method like find_all.
However when you click on that then you will see this.
What it means is that find_all is an alias for select.
In your code you can write find_all or select and it would do the same thing.
Similarly let's see method collect in the sidebar.
Once you click on it you will be taken to the method map.
Method collect is an alias to method map.