Generate Letters to Represent Number Using Ruby

Generate letters to represent number using ruby?

class Numeric
  Alph = ("a".."z").to_a
  def alph
    s, q = "", self
    (q, r = (q - 1).divmod(26)); s.prepend(Alph[r]) until q.zero?
    s
  end
end

3.alph
# => "c"
26.alph
# => "z"
27.alph
# => "aa"
4123.alph
# => "fbo"

Generate array of all letters and digits

[*('a'..'z'), *('0'..'9')] # doesn't work in Ruby 1.8

or

('a'..'z').to_a + ('0'..'9').to_a

or

(0...36).map{ |i| i.to_s 36 }

(the Integer#to_s method converts a number to a string representing it in a desired numeral system)

Assign number to alphabet in array

Here's one way:

arr.map {|ch| ch.ord - 'A'.ord + 10}

How can I generate random mixed letters and numbers in Ruby

How about this:

def random_tuple(length)
    letters_and_numbers = "abcdefghijklmnopqrstuvwxyz0123456789"
    answer = ""
    length.times { |i| answer << letters_and_numbers[rand(36)] }
    answer
end

output = ""
500.times { |i| output << random_tuple(8) + "\n" }

You could also have the function append the newline, but I think this way is more general.

Generate Unique Random String With Letters And Numbers In Lower Case

If you are using ruby 1.9.2 you can use SecureRandom:

irb(main):001:0> require 'securerandom'
=> true
irb(main):002:0> SecureRandom.hex(13)
=> "5bbf194bcf8740ae8c9ce49e97"
irb(main):003:0> SecureRandom.hex(15)
=> "d2413503a9618bacfdb1745eafdb0f"
irb(main):004:0> SecureRandom.hex(32)
=> "432e0a359bbf3669e6da610d57ea5d0cd9e2fceb93e7f7989305d89e31073690"

How to generate a random string in Ruby

(0...8).map { (65 + rand(26)).chr }.join

I spend too much time golfing.

(0...50).map { ('a'..'z').to_a[rand(26)] }.join

And a last one that's even more confusing, but more flexible and wastes fewer cycles:

o = [('a'..'z'), ('A'..'Z')].map(&:to_a).flatten
string = (0...50).map { o[rand(o.length)] }.join

If you want to generate some random text then use the following:

50.times.map { (0...(rand(10))).map { ('a'..'z').to_a[rand(26)] }.join }.join(" ")

this code generates 50 random word string with words length less than 10 characters and then join with space

function that returns the number of letters that repeat in a string

Here is an orthodox way to do it:

'sldhelanlaskjkajksda'.each_char.group_by(&:itself).count{|_, v| v.length > 1}
# => 6

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The reason your code does not work is because, (i) once the i2 loop terminates, you increment i1, and try for another i2 loop in the next i1 iteration, but since i2 hasn't been touched after failed to satisfy the loop condition, it will not satisfy the condition again, and the i2 loop will never run again, and (ii) you are initializing i2 to a constant.

To fix it, initialize i2 within i1 loop at the beginning, and initialize it to i2 = i1 + 1, not 1.

ruby - How can I generate an array of every combination of letters and numbers of a given length?

alphanum = [*?a..?z, *?0..?9]
length.times.flat_map { |l|
  alphanum.repeated_permutation(l + 1).map(&:join)
}

Note that length > 3 will give you a lot of results.

EDIT: As meagar says, this is very memory-intensive. An Enumerator-based answer (not as pretty, but won't kill your memory):

e = Enumerator.new do |y|
  length.times do |l|
    alphanum.repeated_permutation(l + 1).each do |p|
      y << p.join
    end
  end
end

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