In this tutorial we will generate groups of letters, numbers, and both! The ability to copy groups of letters and numbers is essential for copying callsigns well - especially during CW contests!

Four groups of random letters

We can generate words containing random letters by calling random_letters. We can also indicate the size and quantity of words required by passing random_letters the parameters as shown below:

# :size is size of group
# :count is number of groups to generate

random_letters(:size => 5, :count => 4)

The words produced can then be filtered further in the normal way.

  # letter_number_groups.rb

require 'cw'

cw do
  name " 4 letter groups, of 8 characters (15 wpm)"
  random_letters(:count => 4, :size => 8)
  wpm    15

Four groups of random numbers

The random_numbers command works in a similar manner to random_letters

  # letter_number_groups_2.rb

require 'cw'

cw do
  name " 4 number groups, 6 characters (15 wpm)"
  random_numbers(:count => 4, :size => 6)
  wpm 15

Four groups of mixed letters and numbers

There is also a command called random_alphanumeric which will generate groups of mixed numbers and letters. random_letters_numbers is an alias for random_alphanumeric and may be used if preferred.

  # letter_number_groups_3.rb

require 'cw'

cw do
  name " 4 groups of mixed letters and numbers with a size of 6 characters (12 wpm)"
  random_letters_numbers(:count => 4, :size => 6)
  wpm 12

Using Ruby to generate more complex groupings

Since a cw-script is written in the Ruby language, we may utilize the power of Ruby within our tests to create groupings as complex as we like.

Below is an example of generating eight groups consisting of:

  • four letter groups, each containing a letter ‘h’
  • four number groups, each containing a number ‘5’
  • the resulting eight groups are then shuffled
  # letter_number_groups_4.rb

require 'cw'

cw do
  name " 4 number groups, 6 characters (30 wpm)"
  random_numbers(:size => 5)
  word_count 4
  temp = words()
  random_letters(:size => 5)
  word_count 4
  self.words += temp
  wpm 30