How to convert String to Boolean in Ruby?

In this article, we will learn how to convert string to Boolean in Ruby using various methods. Let’s understand each of them with the help of examples.

Converting string to Boolean using String#casecmp

casecmp method compares two strings while ignoring the case and returns 0 if they are equal, -1 if the receiver precedes the argument, and 1 if the receiver follows the argument alphabetically.

Syntax:

string.casecmp(“true”).zero?

Example: In this example we compare the given string with “true” while ignoring case. If the strings are equal, it returns 0. We use this property to check if the result of casecmp is zero to determine if the string represents true.

Ruby

def convert_to_boolean_using_casecmp(string)
  string.casecmp("true").zero?
end

# Test examples
string1 = "True"
string2 = "false"
string3 = "Yes"

 
puts "String: #{string1}, Boolean Value: #{convert_to_boolean_using_casecmp(string1)}"  # Output: true
puts "String: #{string2}, Boolean Value: #{convert_to_boolean_using_casecmp(string2)}"  # Output: false
puts "String: #{string3}, Boolean Value: #{convert_to_boolean_using_casecmp(string3)}"  # Output: true

Output

String: True, Boolean Value: true
String: false, Boolean Value: false
String: Yes, Boolean Value: false

Converting string to Boolean using String#downcase

String#downcase converts the string to lowercase and then we compare it with “true” to check if it represents true..

Syntax:

string.downcase == “true”

Example: In this example we convert the given string to lowercase using downcase and then compares it with “true”. If the lowercase string matches “true”, it returns true.

Ruby

def convert_to_boolean_using_downcase(string)
  string.downcase == "true"
end

# Test examples
string1 = "True"
string2 = "false"
string3 = "Yes"

 
puts "String: #{string1}, Boolean Value: #{convert_to_boolean_using_downcase(string1)}"  # Output: true
puts "String: #{string2}, Boolean Value: #{convert_to_boolean_using_downcase(string2)}"  # Output: false
puts "String: #{string3}, Boolean Value: #{convert_to_boolean_using_downcase(string3)}"  # Output: true

Output

String: True, Boolean Value: true
String: false, Boolean Value: false
String: Yes, Boolean Value: false

Convert string to Boolean using Regular Expressions

Regular expressions can be employed to match specific patterns in strings, such as “true” or “false”, and then convert them to Boolean values.

Syntax:

!!(string =~ /^(true|t|yes|y)$/i)

Example: In this example we uses a regular expression /^(true|t|yes|y)$/i to match strings like “true”, “t”, “yes”, or “y” regardless of case. The expression !!(string =~ /^(true|t|yes|y)$/i) returns true if the string matches the pattern, otherwise false.

Ruby

def convert_to_boolean_using_regex(string)
  !!(string =~ /^(true|t|yes|y)$/i)
end

# Test examples
string1 = "True"
string2 = "false"
string3 = "Yes"

 
puts "String: #{string1}, Boolean Value: #{convert_to_boolean_using_regex(string1)}"  # Output: true
puts "String: #{string2}, Boolean Value: #{convert_to_boolean_using_regex(string2)}"  # Output: false
puts "String: #{string3}, Boolean Value: #{convert_to_boolean_using_regex(string3)}"  # Output: true

Output

String: True, Boolean Value: true
String: false, Boolean Value: false
String: Yes, Boolean Value: true