Stripping the first character of a string

Question

i have

string = "$575.00 "
string.to_f
// => 0.0

string = "575.00 "
string.to_f
// => 575.0

the value coming in is in this format and i need to insert into a database field that is decimal any suggestions

"$575.00 " 

Answer 1

We did this so often we wrote an extension to String called cost_to_f:

class String
  def cost_to_f
    self.delete('$,').to_f
  end
end

We store such extensions in config/initializers/extensions/string.rb.

You can then simply call:

"$5,425.55".cost_to_f   #=> 5425.55

If you are using this method rarely, the best bet is to simply create a function, since adding functions to core classes is not exactly something I would recommend lightly:

def cost_to_f(string)
  string.delete('$,').to_f
end

If you need it in more than one class, you can always put it in a module, then include that module wherever you need it.

---

One more tidbit. You mentioned that you need to process this string when it is being written to the database. With ActiveRecord, the best way to do this is:

class Item < ActiveRecord::Base
  def price=(p)
    p = p.cost_to_f if p.is_a?(String)  
    write_attribute(:price, p)
  end
end

---

EDIT: Updated to use String#delete!