In this lesson we are going to ephasize once again that
in Ruby the correct way is not to use an external accumulator
as shown below.
Here what we are doing is that we are keeping an external accumulator doubled_array and to
this array we keep putting the transformed values.
Anytime we are keeping an external accumulator like this then we need to pause and think
what exactly we are trying to do here. Are we doing data transformation. In the above case
we are taking each element and we are transforming the data and then we are pushing the transformed
data to the external accumulator. Well we have map to handle data transformations.
In some cases we don't want data transformation but we want to filter the records. For that we can use
filter
or
reject.
Sometimes we want the first element that matches the given condition. For that use find.
If you want to select all the elements then use
find_all
which is an alias for method select.