Ruby: How to convert a string to boolean

Question

I have a value that will be one of four things: boolean true, boolean false, the string \"true\", or the string \"false\". I want to convert the string to a boolean if it i

Answer 1

Close to what is already posted, but without the redundant parameter:

class String
    def true?
        self.to_s.downcase == "true"
    end
end

usage:

do_stuff = "true"

if do_stuff.true?
    #do stuff
end

Answer 2

In a rails 5.1 app, I use this core extension built on top of ActiveRecord::Type::Boolean. It is working perfectly for me when I deserialize boolean from JSON string.

https://api.rubyonrails.org/classes/ActiveModel/Type/Boolean.html

# app/lib/core_extensions/string.rb
module CoreExtensions
  module String
    def to_bool
      ActiveRecord::Type::Boolean.new.deserialize(downcase.strip)
    end
  end
end

initialize core extensions

# config/initializers/core_extensions.rb
String.include CoreExtensions::String

rspec

# spec/lib/core_extensions/string_spec.rb
describe CoreExtensions::String do
  describe "#to_bool" do
    %w[0 f F false FALSE False off OFF Off].each do |falsey_string|
      it "converts #{falsey_string} to false" do
        expect(falsey_string.to_bool).to eq(false)
      end
    end
  end
end

Answer 3

if value.to_s == 'true'
  true
elsif value.to_s == 'false'
  false
end

Answer 4

A gem like https://rubygems.org/gems/to_bool can be used, but it can easily be written in one line using a regex or ternary.

regex example:

boolean = (var.to_s =~ /^true$/i) == 0

ternary example:

boolean = var.to_s.eql?('true') ? true : false

The advantage to the regex method is that regular expressions are flexible and can match a wide variety of patterns. For example, if you suspect that var could be any of "True", "False", 'T', 'F', 't', or 'f', then you can modify the regex:

boolean = (var.to_s =~ /^[Tt].*$/i) == 0

Answer 5

I have a little hack for this one. JSON.parse('false') will return false and JSON.parse('true') will return true. But this doesn't work with JSON.parse(true || false). So, if you use something like JSON.parse(your_value.to_s) it should achieve your goal in a simple but hacky way.

Answer 6

h = { "true"=>true, true=>true, "false"=>false, false=>false }

["true", true, "false", false].map { |e| h[e] }
  #=> [true, true, false, false]