Date Formatting

date_formatting.txt

# Date Formatting
# From: http://www.ludism.org/mentat/DateCode


# =========================== #
#  FORMAT FOR YEAR 2000-2099  #
# =========================== #
2-digit-year|month|day


# ======================== #
#  FORMAT FOR YEAR 0-3199  #
# ======================== #
31-digit-0:V|2-digit-year|month|day


# ==================== #
#  MONTHS OF THE YEAR  #
# ==================== #
 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C
Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec


# ================== #
#  DAYS OF THE WEEK  #
# ================== #
1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27|28|29|30|31
. . . . . . . . .  A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V


# ==================================== #
#  STANDARD ALPHABET LETTER POSITIONS  #
# ==================================== #
1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26
A B C D E F G H I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z


# =================================== #
#  ALPHABET POSITION MNEMONIC: EJOTY  #
# =================================== #
5 10 15 20 25
E  J  O  T  Y


# ========== #
#  EXAMPLES  #
# ========== #
Today's Date:
125L => (May 21, 2012)

My Birthday:
J821F => (January 15, 1982)

dateCode.rb

# Decode dates encoded in a special format
#
# Example:
#
#   > ruby dateCode.rb 125M
#     => The date is: May 22, 2012

# Define a method to decode the dates
def dateDecode(date)

  # Create a hash of the numbers 10-31
  # and assign them to their corresponding
  # letters
  numbersTo31 = Hash[('A'..'V').zip('10'..'31')]

  # Create a hash of the months of the year
  # and assign them to numbers
  monthNames = {'1' => 'January',  '2' => 'February',  '3' => 'March',
                '4' => 'April',    '5' => 'May',       '6' => 'June',
                '7' => 'July',     '8' => 'August',    '9' => 'September',
                'A' => 'October',  'B' => 'November',  'C' => 'December' }

  # Take the length of the date input and
  # depending on if it's 4 or 5 characters
  # long, assign the needed variables to the
  # correct indexes: century, year, month, day
  #
  # If the length is not 4 or 5 characters
  # long, then output an error message to
  # the console and end the program by
  # exiting
  if date.length == 4
    year = date[0..1]
    month = date[2..2]
    day = date[3..3]
  elsif date.length == 5
    century = date[0..0]
    year = date[1..2]
    month = date[3..3]
    day = date[4..4]
  else
    puts
    puts "Wrong date format. Please try again."
    exit
  end

  # If century exists (by having a length of 5 characters)
  # depending on if the number is higher than 9 or not,
  # create a variable named prefix that will hold either
  # the number 1-9 or one of the letters in the
  # numbersTo31 hash
  #
  # If century doesn't exist (by having a length of 4 characters)
  # then the prefix will equal 20
  prefix = century ? numbersTo31[century] || century : '20'

  # Output a string to the console containing the converted
  # date, along with the extra "The date is: " string
  puts
  puts "The date is: #{monthNames[month]} #{numbersTo31[day] || day}, #{prefix}#{year}"
end

# Call the method and pass ARGV[0] to grab
# input from the user when they run the app
dateDecode(ARGV[0])