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 

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.