Ruby Iterators

In Ruby, iterators are methods that allow you to traverse or iterate over a collection of elements. They provide a way to perform a set of operations on each element of a collection without needing to write repetitive code. Here’s a list of some common iterators in Ruby along with examples:

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each Iterator:

• Iterates over each element of a collection.

numbers = [1, 2, 3, 4, 5]
numbers.each { |n| puts n }  # Output: 1 2 3 4 5

map Iterator:

• Transforms each element of a collection and returns a new array with the transformed values.

numbers = [1, 2, 3, 4, 5]
doubled = numbers.map { |n| n * 2 }
puts doubled.inspect  # Output: [2, 4, 6, 8, 10]

select Iterator:

• Filters elements of a collection based on a condition and returns a new array with the selected elements.

numbers = [1, 2, 3, 4, 5]
evens = numbers.select { |n| n.even? }
puts evens.inspect  # Output: [2, 4]

reduce Iterator:

• Combines all elements of a collection into a single value by applying an accumulator function.

numbers = [1, 2, 3, 4, 5]
sum = numbers.reduce(0) { |acc, n| acc + n }
puts sum  # Output: 15

each_with_index Iterator:

• Iterates over each element of a collection along with its index.

fruits = ['apple', 'banana', 'cherry']
fruits.each_with_index { |fruit, index| puts "#{index}: #{fruit}" }
# Output:
# 0: apple
# 1: banana
# 2: cherry

times Iterator:

• Executes a block a specified number of times.

3.times { |n| puts "Hello, #{n + 1}" }
# Output:
# Hello, 1
# Hello, 2
# Hello, 3

upto and downto Iterators:

• Iterates from a starting value up to or down to an ending value.

1.upto(5) { |n| puts n }  # Output: 1 2 3 4 5
5.downto(1) { |n| puts n }  # Output: 5 4 3 2 1

These are some of the most commonly used iterators in Ruby. They provide a concise and expressive way to work with collections of data.