We will be discussing two iterators here each and collect.
Ruby each loop.
We will cover while loops do while loops and for loops.
Ruby while loop n x 1 end output.
X 1 y 11 until x y do print x.
The each loop is perhaps the most useful of all the loops.
In ruby arrays and hashes can be termed collections.
The while loop will print out an array and use a variable to increment and keep track of what it is printing out.
The each iterator returns all the elements of an array or a hash.
This works exactly like the each method for an array object with one crucial difference.
This chapter details all the loop statements supported by ruby.
Arrays and hashes define the each method and many other ruby objects do too.
Since almost all computing tasks use lists of variables and have to do something with each of them in the list the each loop is by far the most common loop in ruby code one thing to note here is the argument to the loop s block of.
Executes code once for each element in expression.
It s the ruby way of doing repeat until done.
The simplest way to create a loop in ruby is using the loop method loop takes a block which is denoted by.
For a hash you create two elements one for the hash key and one for the value.
Some operations in computer programming are best served with a loop.
Let s see how a for loop looks like.
As we re looping through each item in the array we re using a specific pattern getting an item out of the array and working with it in a specific way.
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.
Those coming from an imperative language might be more familiar with the for loop.
Ruby loops loops in ruby are used to execute the same block of code a specified number of times.
If the condition is false the loop will continue to execute.
The each loop.
And if it is we call break which stops everything and gets out of the loop.
Syntax collection each do variable code end.
Iterators return all the elements of a collection one after the other.
1 2 3 each do i break if i 3 puts i end 1 2.
In this example we check to see if the value of i is equal to 3.
You could say that we re iterating over each item in the array.
Each loop will take a list of variables and run a block of statements for each of them.
Like a while loop the condition x 11 is checked when entering the loop and each time the loop body executes.
The for in loop calls the each method of the specified object.
As that iterator yields values the for loop assigns each value or each set of values to the specified variable or variables and then executes the code in body.
Let s look at these in detail.
The ruby each loop the ruby method each allows you to go over a list of items without having to keep track of the number of iterations or having to increase some kind of counter.