Ruby Output

You can display output to the screen in Ruby using print statements such as puts, print and p. Here's how these methods work:

Let's look at each of these methods one by one.

Ruby puts Method

The puts method in Ruby prints content and automatically adds a newline at the end. For example,

# Print a sentence to the screen using puts
puts "Ruby tutorials for beginners!"

# Print another sentence to the screen
puts "Brought to you by Programiz!"

Output

Ruby tutorials for beginners!
Brought to you by Programiz!

Here, we used two puts statements to print two sentences.

As you can see, the second sentence is printed in a new line.

That's because puts adds a newline at the end of the text it prints. Thus, the next print statement will print in the next line.

Ruby print Method

The print method works similarly, but does not add a newline. This means subsequent output appears on the same line. For example,

# Print a sentence to the screen using print
print "Ruby tutorials for beginners!"

# Print another sentence to the screen
print "Brought to you by Programiz!"

# Output: Ruby tutorials for beginners!Brought to you by Programiz!

Here, we used two print statements to print two sentences.

Because print doesn't move the cursor to the next line, the second message appears immediately after the first.

Add a Newline with the print Method

You can manually insert a newline inside print by using the newline character \n. For example,

# Add a newline character at the end of the string
print "Ruby tutorials for beginners!\n"

print "Brought to you by Programiz!"

Output

Ruby tutorials for beginners!
Brought to you by Programiz!

Ruby p Method

The p method is commonly used for debugging. It prints values in a developer-friendly way:

• Strings are shown with quotation marks.
• Other values (like numbers, nil, true, false, etc.) are shown as-is.

Example

# Print a string
p "Ruby tutorials for beginners!"

# Print a number
p 34

# Print 'nil' value
p nil

# Print boolean values 'true' and 'false'
p true
p false

Output

"Ruby tutorials for beginners!"
34
nil
true
false

As you can see, the string value is printed with quotations, but the other values are printed without them.

greeting = "Hello, World"

# Print greeting using p
p greeting

# Print greeting using inspect
puts greeting.inspect

"Hello, World"
"Hello, World"

puts obj.inspect

Example 1: Comparing the Different Print Statements

Let's compare all three print statements using an example:

# Use puts to print a string
puts "Hello, World!"

# Use print to display a string
print "Hello, World! "

# Use p to print a string
p "Hello, World!"

Output

Hello, World!
Hello, World! "Hello, World!"

Here,

• puts adds a newline.
• print keeps output on the same line.
• p shows the value clearly, including quotes.

Example 2: Printing Arrays

Ruby has an interesting difference in how arrays are printed with the various display methods. Let's demonstrate this with an example:

my_array = [1, 2, 3]

puts "Printing Array Using puts:"
puts my_array

print "\nPrinting Array Using print: "
print my_array

print "\n\nPrinting Array Using p: "
p my_array

Output

Printing Array Using puts:
1
2
3

Printing Array Using print: [1, 2, 3]

Printing Array Using p: [1, 2, 3]

As you can see, the print and p methods display the array in array notation.

On the other hand, the puts method displays each array element in separate lines.

Printing Multiple Items

Ruby allows you to print multiple items using a single statement. You can accomplish this in one of two ways:

• By feeding multiple arguments to the method using commas.
• By joining strings together using the + operator.

Note: Don't worry if you're not sure what "arguments" means — you'll learn that soon when we cover methods.

Let's explore these techniques next.

Print Multiple Items Using Commas

You can use commas to separate items you want to print. For example,

name = "Peter"
age = 29

puts "Commas with puts:"
puts "Hello ", name, age

puts "\nCommas with print:"
print "Hello ", name, age

puts "\n\nCommas with p:"
p "Hello ", name, age

Output

Commas with puts:
Hello 
Peter
29

Commas with print:
Hello Peter29

Commas with p:
"Hello "
"Peter"
29

Here, we printed the string "Hello " and the variable name and age using the different printing statements. As you can see,

• puts and p displayed the items in separate lines.
• print displayed the items in the same line and without any space in between them.

Print Multiple Strings Using the + Operator

The + operator joins (concatenates) the different strings you want to print. These strings will be joined in the same line, regardless of whether you use puts or print.

Note: The + operator only joins strings. If you try to use it with a number, Ruby will either raise an error (when one operand is a string) or perform arithmetic addition (if both are numbers).

Example

name = "Peter"

puts "Concatenation with puts:"
puts "Hello " + name

puts "\nConcatenation with print:"
print "Hello " + name

puts "\n\nConcatenation with p:"
p "Hello " + name

Output

Concatenation with puts:
Hello Peter

Concatenation with print:
Hello Peter

Concatenation with p:
"Hello Peter"

Here, we joined a string "Hello " and a string variable name using the + operator. As you can see, the objects are joined in the same line.

age = 29

# Invalid: Joining a string and a number
puts "Age: " + age

# Output: no implicit conversion of Integer into String (TypeError)


# Invalid: Concatenating boolean values
print true + false

# Output: undefined method '+' for true (NoMethodError)

age = 29

# + will add the numbers instead of joining them
puts 12 + age
print 12 + age
p 12 + age

41
4141

age = 29

# Valid: age has been converted to string
puts "Age: " + age.to_s

# Valid: Both boolean values are now strings
puts true.to_s + false.to_s

# Concatenate two numbers by converting them to strings
puts 12.to_s + age.to_s

Age: 29
truefalse
1229

String Interpolation: Print Text and Variables Together

In Ruby, you can insert variables directly into strings using interpolation with #{}. This works only with double quotes. For example,

# Create name variable
name = "Ash Ketchum"

# Create age variable
age = 10

# Print the variables inside a string
puts "Hello, #{name}! You are #{age} years old."

# Output: Hello, Ash Ketchum! You are 10 years old.

Here,

• #{name} - Inserts the value of the name variable inside the printed string.
• #{age} - Inserts the value of the age variable inside the printed string.

Note: In string interpolation, the values of the variables are inserted as strings. Thus, even though age is a variable of number type, Ruby automatically converts it to a string during interpolation.