Ruby: how to generate unique alphabetic string in ruby

SecureRandom has a method choose which:

[...] generates a string that randomly draws from a source array of characters.

Unfortunately it's private, but you can call it via send:

SecureRandom.send(:choose, [*'a'..'z'], 8)
#=> "nupvjhjw"

You could also monkey-patch Random::Formatter:

module Random::Formatter
  def alphabetic(n = 16)
    choose([*'a'..'z'], n)
  end
end

SecureRandom.alphabetic
#=> "qfwkgsnzfmyogyya"

Note that the result is totally random and therefore not necessarily unique.

UUID are designed to have extremely low chance of collision. Since UUID only uses 17 characters, it's easy to change the non-alphabetic characters into unused alphabetic slots.

SecureRandom.uuid.gsub(/[\d-]/) { |x| (x.ord + 58).chr }

Is there any in built method in ruby which will generate unique alphabetic string every time(it should not have numbers only alphabets)?

This is not possible. The only way that a string can be unique if you are generating an unlimited number of strings is if the string is infinitely long.

So, it is impossible to generate a string that will be unique every time.

def get_random_string(length=2)
  source=("a".."z").to_a + ("A".."Z").to_a
  key=""
  length.times{ key += source[rand(source.size)].to_s }
  key
end

How about something like this if you like some monkey-patching, i have set length 2 here , please feel free to change it as per your needs

get_random_string(7)

I used Time in miliseconds, than converted it into base 36 which gives me unique aplhanumeric value and since it depends on time so, it will be very unique.

Example:

Time.now.to_f.to_s.gsub('.', '').ljust(17, '0').to_i.to_s(36) # => "4j26m4zm2ss"

Take a look at this for full answer: https://stackoverflow.com/a/72738840/7365329