Question

I am new at Ruby on Rails.
I was trying to validate format of one of the attribute to enter only float.

validates :price, :format => { :with => /^[0-9]{1,5}((\.[0-9]{1,5})?)$/, :message => "should be float" }

but when I enter only character in price, it accepts it and show 0.0 value for price.
can anybody tell, what is wrong in this or why this happens?

Answer 1

A float is a number and regular expressions are for strings.

It appears that when you enter a string for the float, it gets converted as 0.0 automatically by Rails.

Do you have a default (0.0) on the column? If yes, then you may try removing it and use validates_presence_of :price only.

---

Something to try: instead of putting the string directly into the price column, put it into a price_string attr and use a before_save callback to try to convert the string to price. Something like that:

attr_accessor :price_string

before_save :convert_price_string

protected
  def convert_price_string
    if price_string
      begin
        self.price = Kernel.Float(price_string)
      rescue ArgumentError, TypeError
        errors.add(ActiveRecord::Errors.default_error_messages[:not_a_number])
      end
    end

And in your form, change the name of the text_field to :price_string.