Writing Custom Iterators in Ruby

Passing Argument in Custom Iterators

To give argument values to the block, we will use a comma-separated list of expressions after the ‘yield’ statement. The parameter values, like method invocation, can optionally be contained in parentheses. 

The ‘yield’ function is demonstrated in the following simple iterator:

#!/usr/bin/ruby
# Code for Passing argument in custom iterators in Ruby
def sequence(s1, t1, u1)
   x = 0
while(x < s1)
   yield t1*x + u1
   x += 1
end
end
sequence(6, 8, 4) {|y| puts y }

You can also try this code with Online Ruby Compiler

Run Code

Output:

Here's another specified situation of a custom iterator in action. Assume we're creating a game that needs to determine whether or not a character's name is valid. We're only interested in character names that have more than three characters.

#!/usr/bin/ruby
characterNames = ['Paul', 'Ada', 'Jonathan', 'Noah', 'Ben']

def characterCheckerValidity(character_names)
   character_names.each do |character_name|
       puts "Is the name '#{character_name}' a valid character?"
       yield(character_name)
   end
end

characterCheckerValidity(characterNames) do |character_name|
   if character_name.length > 3
       puts "You can set this name as it is a valid character name :)"
   else
       puts "You cannot set this name as it is an invalid character name :("
   end
end

You can also try this code with Online Ruby Compiler

Run Code

Output:

Frequently Asked Questions

In Ruby, what is the yield statement?

The yield statement is used to invoke a method block with a value.

What exactly are Ruby iterators?

Iterator is a term used in object-oriented programming. Iteration is the repetition of a single action, similar to a loop. The loop method is the most basic Iterator. They return all the components of a collection one by one. Arrays and hashes are examples of collections.

In Ruby, how many iterators are there?

The iterators present in Ruby are- each Iterator, times Iterator, upto and downto Iterator, step iterator, and each_line Iterator.

How are blocks written in Ruby?

Curly braces or a do-end statement enclose blocks. Do-end is typically used for blocks that cross multiple lines, whereas for blocks that only cross one line. Arguments for blocks should be defined between two pipe ‘|’ Characters.

What exactly are Ruby blocks?

Other programming languages refer to Ruby code blocks as closures. It is made up of a series of codes that are always separated by braces or written between do...end.

Conclusion

In this article, we have extensively discussed the concept of custom iterators in Ruby. We started with the introduction of iterators and custom iterators in Ruby and concluded with examples and passing arguments in custom iterators.

After reading about the custom iterators in ruby, are you not feeling excited to read/explore more articles on the topic of ruby? Don't worry; Coding Ninjas has you covered. To learn, see Blocks and Iterators in Ruby, External Iterators in Ruby, and Hashes in Ruby.

Refer to our Guided Path on Coding Ninjas Studio to upskill yourself in Data Structures and Algorithms, Competitive Programming, JavaScript, System Design, and many more! If you want to test your capacity in coding, you may check out the mock test series and participate in the contests hosted on the Coding Ninjas Studio website. But if you have just started learning and are looking for questions asked by tech giants like Amazon, Microsoft, Google, Uber, etc., you must look at the problems, interview experiences, and interview bundle for placement preparations.

You may also consider our courses to give your career an edge over others!

Do upvote our blogs if you find them helpful and engaging!

Happy Learning!