CODEWITHSUNDEEP
rubyintegeryaml
YoYoYo I'm Awesome
YoYoYo I'm Awesome

Reputation: 285

How to extract digits from a string and use them to extract from a YAML file

I'm trying to extract integers from a string and use them to scan through a YAML file like so:

FORMS = YAML.load_file('../email/lib/lists/form_links.yml')

def get_form(form)
  form_num = form.scan(/\d+/)
  data = FORMS['esd_forms'][form_num]
  begin
    if data != nil
      "Form link: #{data}"
    else
      raise StandardError
    end
  rescue StandardError
    "** Form: #{form} is not a valid form name **"
  end
end

YAML file:

esd_forms:
  1: 'http://labornet.com/itc/ESD-1.pdf'
  2: 'http://labornet.com/itc/ESD-2.pdf'
  3: 'http://labornet.com/itc/ESD-3.pdf'
  4: 'http://labornet.com/itc/ESD-4.pdf'
  5: 'http://labornet.com/itc/ESD-5.pdf'
  6: 'http://labornet.com/itc/ESD-6.pdf'
  7: 'http://labornet.com/itc/ESD-7.pdf'
  8: 'http://labornet.com/itc/ESD-8.pdf'
  9: 'http://labornet.com/itc/ESD-9.pdf'
  10: 'http://labornet.com/itc/ESD-10.pdf'
  11: 'http://labornet.com/itc/ESD-11.pdf'
  03: 'http://labornet.com/itc/OCIO-IT-03.pdf'
  07: 'http://labornet.com/itc/OCIO-IT-07.pdf'
  10: 'http://labornet.com/itc/OCIO-10.pdf'
  13: 'http://labornet.com/itc/ESD-13.pdf'
  14: 'http://labornet.com/itc/ESD-14.pdf'

When I do this I get an error:

wrong argument type Array (expected Regexp)

I don't understand why I'm getting this error. At first I thought it was because the program was returning an array instead of a string, so I tried it in IRB:

irb(main):001:0> form = 'esd-2'
=> "esd-2"
irb(main):002:0> form_num = form.scan(/\d+/)
=> ["2"]
irb(main):003:0> puts form_num
2

To me, it seems like I'm doing this correctly. What am I doing wrong?

Upvotes: 1

Views: 915

Answers (1)

Arie Xiao
Arie Xiao

Reputation: 14082

String#scan returns all the occurrences in the String that matches the regular expression, in an array.

You see in your irb session when you execute form_num = form.scan(/\d+/), it actually returns an array with 1 element ["2"].

If you want to return the first matched segment, you can use String#[]:

form = 'esd-2'
form_num = form[/\d+/]
#=> "2"

Besides, if you need to examine what is stored in an variable, p will be a better choice than puts. And irb actually use p to output the expression result by default as you see in your irb session.

form = 'esd-2'
form_num = form.scan(/\d+/)
puts form_num
#=> 2
p form_num
#=> ["2"]

Upvotes: 1

Related Questions