Ruby Regex Code String

Question

I have the following logic

def insert_type(type_list, user_input)
  case user_input
  when user_input == 'library_1'
    type_list.slice!('library_' + RegEx for any digit after library_ and stop right there + '__')
    type_list << user_input << '__'
  when user_input == 'class_A_2'
    type_list.slice!('class_' + RegEx for any digit after class_ and stop right there + _A + '__')
    type_list << user_input << '__'
  end
end

I tried to do the following

[l][i][b][r][a][r][y][_]\d{0,5} #digit from 0 to 99999

It does work, but there should be a more conventional way out there where I could start with l, and ends with the underscore, then add the number since type_list could be:

puts type_list
=> "username_John__userid_58173__userpass_8adsh20__class_A_2__library_0__"

I don't really get what you want to do. Can't you just split along __ (double underscore)? — nhahtdh
– nhahtdh, Commented Jan 12, 2014 at 7:50
@nhahtdh true, if I know how to take from 'l' to 'y' from 'library' I could do it up to __. :D but how do you that? — user3163916
– user3163916, Commented Jan 12, 2014 at 7:54
Not sure what you want to do, but if you split type_list with ruby-doc.org/core-2.1.0/String.html#method-i-split along __, you get [username_John, userid_58173, userpass_8adsh20, class_A_2, library_0]. Then for each member, you can split it again. — nhahtdh
– nhahtdh, Commented Jan 12, 2014 at 7:57

brandonscript · Accepted Answer · 2014-01-12 08:02:08Z

1

What you want is this:

\w+?(\d{1,5})

Or if you want a specific word, then:

library_(\d{1,5})

It will non-greedily capture the word characters, then add the numerical value to the first capture group.

Basic example: http://regex101.com/r/xE0sM0
Using your output: http://regex101.com/r/aV6yX6 (not sure if you want to match this?)

Explained:

Any word character, including _, non greedy until we find a number
Any number, from 1 to 5 digits (using {0,5} here would actually be 0 to 5 digits)
Wrapping the digit in parentheses () allows the value to be captured.

edited Jan 12, 2014 at 8:02

answered Jan 12, 2014 at 7:55

brandonscript

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3 Comments

user3163916 Over a year ago

thank you, but what if the word that I wanted is library? Since type_list has other words inside the string and library isn't always be the first word?

brandonscript Over a year ago

If you specifically want library, then just use library_(\d{1,5})

user3163916 Over a year ago

:O Didn't know you could do that! Thank you, sir!

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