String "false" to_bool ... or how to convert Rails/SimpleForm radio buttons to boolean

README.md

This gist was writen in 2012 and it was solving specific problem in Rails & SimpleForm. Some fellow developers were pointing out this may be out dated concept. That's why I advise everyone to read comment section bellow to have a full grasp of alternative solutions

other sources that may be helpful to understand why this may not be best idea:

• Why Ruby doesn’t have a Boolean class

string_boolean.rb

module StringToBoolean
  def to_bool
    return true if self == true || self =~ (/^(true|t|yes|y|1)$/i)
    return false if self == false || self.blank? || self =~ (/^(false|f|no|n|0)$/i)
    raise ArgumentError.new("invalid value for Boolean: \"#{self}\"")
  end
end
class String; include StringToBoolean; end

module BooleanToBoolean
  def to_bool;return self; end
end

class TrueClass; include BooleanToBoolean; end
class FalseClass; include BooleanToBoolean; end

z_alternative_output

# However there is also better practice to do it by using 

ActiveRecord::ConnectionAdapters::Column.value_to_boolean( something )

2.0.0dev :019 > ActiveRecord::ConnectionAdapters::Column.value_to_boolean('1')
 => true 
2.0.0dev :020 > ActiveRecord::ConnectionAdapters::Column.value_to_boolean('0')
 => false 
2.0.0dev :021 > ActiveRecord::ConnectionAdapters::Column.value_to_boolean('true')
 => true 
2.0.0dev :022 > ActiveRecord::ConnectionAdapters::Column.value_to_boolean('false')
 => false 
2.0.0dev :023 > ActiveRecord::ConnectionAdapters::Column.value_to_boolean('nil')
 => false 
2.0.0dev :024 > ActiveRecord::ConnectionAdapters::Column.value_to_boolean('t')
 => true 
2.0.0dev :025 > ActiveRecord::ConnectionAdapters::Column.value_to_boolean('cat')
 => false 
2.0.0dev :026 > ActiveRecord::ConnectionAdapters::Column.value_to_boolean(true)
 => true 
2.0.0dev :027 > ActiveRecord::ConnectionAdapters::Column.value_to_boolean(false)

2.0.0dev :035 > ActiveRecord::ConnectionAdapters::Column.value_to_boolean(1)
 => true 
2.0.0dev :036 > ActiveRecord::ConnectionAdapters::Column.value_to_boolean(2)
 => false 
2.0.0dev :037 > ActiveRecord::ConnectionAdapters::Column.value_to_boolean(0)
 => false 

in rails place the file to config/initializers/string_boolean.rb

than you can do

  "false".to_bool
  #=>  false

Usage: Rails radio button helpers are sending you "false" as string => you need to convert them to boolean, otherwise "false".present? == true

Update: extended with to_bool solution for TrueClass and FalseClass from http://stackoverflow.com/a/3028378/473040

this way you can do

 "false".to_bool #=> false
  false.to_bool  #=> false

and

   def my_method(args)
      if args.is_a? Boolean
         "yahoo it's boolean"
      else
         "is something else"
       end
   end

main reason for implementation is when you have model settra method, that can be set from f.e. simple form radio buttons

    def foo=(arg)
        @foo=arg.to_bool
    end

instead of

 def foo=(arg)
    @foo= (arg.is_a?(TrueClass) || arg.is_a?(FalseClass)) ? arg : (arg == "true" || arg =="yes" ) 
 end

It turns out that if you're using Mongoid, then Boolean is declared as a class inside of Mongoid. This prevents the gist from working if using Mongoid since it's trying to redefine Boolean as a module. So I've forked the gist and renamed the module Boolean to BooleanToBoolean.

module BooleanToBoolean
  def to_bool;return self; end
end

class TrueClass; include BooleanToBoolean; end
class FalseClass; include BooleanToBoolean; end

good point, thx for this, I'll update my gits

ok, colleague pointed out that one can use also ActiveRecord::ConnectionAdapters::Column.value_to_boolean("true") ...updating my gits, thx D.D.

It seems that ActiveRecord::ConnectionAdapters::Column.value_to_boolean("true") is deprecated
http://apidock.com/rails/ActiveRecord/ConnectionAdapters/Column/value_to_boolean/class
Anyway, thanks for the gist.

I think it is still supported in Rails 4.0

http://www.rubydoc.info/docs/rails/ActiveRecord/ConnectionAdapters/Column.value_to_boolean

This variation attaches to_bool to most value objects and returns false instead of raising an error when a value isn't expected:

module ToBoolean
  def to_bool
    return true if self == true || self.to_s.strip =~ /^(true|yes|y|1)$/i
    return false
  end
end

class NilClass; include ToBoolean; end
class TrueClass; include ToBoolean; end
class FalseClass; include ToBoolean; end
class Numeric; include ToBoolean; end
class String; include ToBoolean; end

This way:

nil.to_bool           => false
false.to_bool         => false
"false".to_bool       => false
0.to_bool             => false
2.to_bool             => false
"0".to_bool           => false
"2".to_bool           => false
"1.0".to_bool         => false
1.0.to_bool           => false
"no".to_bool          => false
"hamster".to_bool     => false

1.to_bool             => true
"1".to_bool           => true
true.to_bool          => true
"true".to_bool        => true
"true  ".to_bool      => true
"TRUE".to_bool        => true
"  TrUE   ".to_bool   => true
"yes".to_bool         => true
"YES".to_bool         => true
"y".to_bool           => true
"Y".to_bool           => true

I have just made the wannabe_bool gem to convert strings, integers, symbols and nil values to boolean, using a #to_b method.
https://github.com/prodis/wannabe_bool

'true'.to_b # => true
1.to_b      # => true
:true.to_b  # => true

'false'.to_b # => false
0.to_b       # => false
:false.to_b  # => false
nil.to_b     # => false

# and more

ok from Rails 4.2 ActiveRecord::ConnectionAdapters::Column.value_to_boolean("true") is depricated, use:

ActiveRecord::Type::Boolean.new.type_cast_from_database(value)

Works the same way, one different is that type_cast_form_database returns nil when value = nil.

One other thing I've noticed is that if the value is y or n I'm getting:

DEPRECATION WARNING: You attempted to assign a value which is not explicitly `true` or `false` to a boolean column. Currently this value casts to `false`. This will change to match Ruby's semantics, and will cast to `true` in Rails 5. If you would like to maintain the current behavior, you should explicitly handle the values you would like cast to `false`.

... so use only strings "true" and "false" in your radio buttons / check boxes

ActiveRecord::Type::Boolean.new.type_cast_from_user(value)

Sometimes I like to be able to call to_bool on something that might be nil, so I alias the Ruby boolean operator default to everything and then further refine String:
app/config/initializers/to_bool.rb

    class Object
        def to_bool
            return !!self
        end
    end

    class String
        def to_bool
            return true if self == true || self =~ (/(true|t|yes|y|1)$/i)
            return false if self == false || self.blank? || self =~ (/(false|f|no|n|0)$/i)
            raise ArgumentError.new("invalid value for Boolean: \"#{self}\"")
        end
    end

Works great for me and seems robust: https://gist.github.com/jameslafa/337e6290115479c2e7e707a8978b7f5a

# config/initializers/to_boolean.rb

module ToBoolean
  def to_bool
    return true if ActiveRecord::ConnectionAdapters::Column::TRUE_VALUES.include?(self)
    return false
  end
end

class NilClass; include ToBoolean; end
class TrueClass; include ToBoolean; end
class FalseClass; include ToBoolean; end
class Numeric; include ToBoolean; end
class String; include ToBoolean; end

If anybody is coming from Rails 5, this method moved again. I had the most luck with:

ActiveRecord::Type::Boolean.new.cast(string)

@nickcampbell18++

@nickcampbell18 thankyou!!!

ActiveRecord::Type::Boolean.new.cast(string)

FTW 🥇

Ruby Facets / to_b

require 'facets/boolean'

[ nil, '', 1, 0, '1', '0', true, false, 'true', 'false', 'yes', 'no' ].each do |value|
  puts "#{value.inspect}: #{value.to_b}"
end

Output

nil: false
"": false
1: true
0: false
"1": true
"0": false
true: true
false: false
"true": true
"false": false
"yes": true
"no": false

@nickcampbell18++

Thank you! @nickcampbell18 +100

Thank you! @nickcampbell18 +2999

Please close this gist man, It creates so many issues, i start to see this code into a lot of places, create pr to ruby if you think it's a right way to handle booleans. Thanks a lot!

@OpakAlex

i start to see this code into a lot of places

and all are pointing to this gist as a single source ?

create pr to ruby

There is a good reason why this is not introduced in Ruby (or the notion of single boolean class which would TrueClass and FalseClass more info ) But this is not about Ruby it's about specifc usecase in Rails and SimpleForm. It was written in 2012 and it was solving an issue. I cannot tell if it's still valid as I didn't use Simple Form in 8 years but I see people having a conversation on this gist which I think is valuable.

if you think it's a right way to handle booleans

I don't, but this gist is not about Ruby

Please close this gist man

I will not as I see value in the comment section. But I welcome if you drop here a comment guiding others how to better approach issue originally described or your thoughts on boolean in Ruby. I'm pretty sure everyone would welcome a constructive comment with a solution

have a lovely day

@equivalent if it's not about ruby, then replace:

class TrueClass; include BooleanToBoolean; end
class FalseClass; include BooleanToBoolean; end

and ask people to use your class without patch ruby. I think if it's not about ruby then use helper method or class, or what you want. If you show how to patch standart ruby class, then make ruby PR.