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

Don't think too much:

bool_or_string.to_s == "true"  

So,

"true".to_s == "true"   #true
"false".to_s == "true"  #false 
true.to_s == "true"     #true
false.to_s == "true"    #false

You could also add ".downcase," if you are worried about capital letters.

Answer 2

If you use Rails 5, you can do ActiveModel::Type::Boolean.new.cast(value).

In Rails 4.2, use ActiveRecord::Type::Boolean.new.type_cast_from_user(value).

The behavior is slightly different, as in Rails 4.2, the true value and false values are checked. In Rails 5, only false values are checked - unless the values is nil or matches a false value, it is assumed to be true. False values are the same in both versions: FALSE_VALUES = [false, 0, "0", "f", "F", "false", "FALSE", "off", "OFF"]

Rails 5 Source: https://github.com/rails/rails/blob/5-1-stable/activemodel/lib/active_model/type/boolean.rb