Let's look at the documentation for method
select.
The documentation has following two lines at the top.
In the first line what the documentation is saying that the method select take a block.
What comes after the "→" means that the method will return.
In this case the first line is returning an array.
In other words if a block is passed to select then it will return an array.
The second line says that if no block is passed then an enumerator will be returned.
enumerator is an advance topic and currently we are not discussing it.
Docs for method map
Let's take one more example. we are going to see the documentation for
map.
Here also we see the same thing.
Docs for method max
Now let's see the documentation for method max.
Here we can see that max can be used in four different ways and in different conditions it returns different thing.
- Line 1: If no argument is passed then it returns an element.
- Line 2: If a number is passed then it returns an array.
- Line 3: If a block is passed then it returns an element.
- Line 4: If both a number and a block is passed then it returns an array.