for loop is a control flow statement for specifying iteration. Specifically, a for loop functions by running a section of code repeatedly until a certain condition has been satisfied.

Example 1: Basic for loop

    for i in 1..5 do
      puts "Value of i is #{i}"
    end
        In this example, the program uses a for loop to iterate over a range of numbers from 1 to 5 (inclusive) and print the current value of i.

Example 2: for loop with array

    fruits = ["apple", "banana", "cherry"]
    for fruit in fruits do
      puts "I like #{fruit}s"
    end
    
    Output :
            Value of i is 1
            Value of i is 2
            Value of i is 3
            Value of i is 4
            Value of i is 5

        In this example, the program uses a for loop to iterate over an array of fruits and print a message for each one.


Example 3: for loop with hash

    person = {name: "Alice", age: 30, occupation: "programmer"}
    for key, value in person do
      puts "#{key.capitalize}: #{value}"
    end
    
    Output : 
        Name: Alice
	Age: 30
	Occupation: programmer

        In this example, the program uses a for loop to iterate over a hash and print each key-value pair with a capitalized key.


Example 4: for loop with step

    for i in 0.step(by: 2, to: 10) do
      puts "Value of i is #{i}"
    end
    
    Output:
    Value of i is 0
	Value of i is 2
	Value of i is 4
	Value of i is 6
	Value of i is 8
	Value of i is 10

        In this example, the program uses a for loop with the step method to iterate over a range of numbers from 0 to 10 (inclusive) in increments of 2.


Example 5: Nested for loops

    for i in 1..3 do
      for j in 1..3 do
        puts "#{i} x #{j} = #{i*j}"
      end
    end
    Output: 
    1 x 1 = 1
    1 x 2 = 2
    1 x 3 = 3
    2 x 1 = 2
    2 x 2 = 4
    2 x 3 = 6
    3 x 1 = 3
    3 x 2 = 6
    3 x 3 = 9

        In this example, the program uses nested for loops to print the multiplication table from 1 to 3. The outer loop iterates over i and the inner loop iterates over j, so each combination of i and j is printed.