Yield returns the last evaluated expression from inside the block.
Ruby return value from block.
So far in our two examples above we did not do anything with the return values of the block.
The following code returns the value x y.
Because ruby allows implicit block passing you can call all methods with a block.
Def my method value yield puts value is.
New 3 index index 2 0 1 4 common gotchas when sending the second parameter the same object will be used as the value for all the array.
Remember that we said a block returns a value just like methods do.
A ruby block is useful because it allows you to save a bit of logic code use it later.
It finds and calls a passed block so you don t have to add the block to the list of arguments the method accepts.
Whenever a block is appended to a method call ruby automatically converts it to a proc object but one without an explicit name.
It returns each value of the array one by one to the block.
The method however has a way to access this proc by means of the yield statement.
See fun with ruby.
Value end my method do 2 end value is 2.
Break within a block.
This concept which is sometimes called closure means that a proc will carry with it values like local variables and methods from the context where it was defined.
The collect iterator returns all the elements of a collection.
The method select then returns this array and ruby will pass it to the method p which prints the array out to the screen.
As you can see name is not available to my method because it s local to the block.
In the last form an array of the given size is created.
Returning in blocks overwrites outside return values for an example.
Like the array these elements are placeholders that are used to pass each key value pair into the code block as ruby loops through the hash.
Break is only valid within a block.
Each element in this array is created by passing the element s index to the given block and storing the return value.
Methods return the value of the last statement executed.
It lets you jump out of a block and returns nil or the provided argument to.
For a hash you create two elements one for the hash key and one for the value.
If it doesn t call yield the block is ignored.
Thus the code above prints out 1.
This works exactly like the each method for an array object with one crucial difference.
The value is stored in the variable i and then displayed on the screen.
Implicit block passing works by calling the yield keyword in a method.
Syntax collection collection collect the collect method need not always be associated with a block.
Def do something with block return no block given unless block given.
