桁区切りとフラグの悪夢

separate_and_flags.php

<?php
 
$month = array_combine(
    array(4, 5, 6, 7, 8, 9, 10, 11, 12, 1, 2, 3),
    str_split('001001000000'));
 
$combo = array();
foreach ($month as $m => $flg) {
    $combo[] = $m . ((boolean) $flg ? '月期' : null);
}
 
var_export($combo);

/**

$ php separate_and_flags.php
array (
  0 => '4',
  1 => '5',
  2 => '6月期',
  3 => '7',
  4 => '8',
  5 => '9月期',
  6 => '10',
  7 => '11',
  8 => '12',
  9 => '1',
  10 => '2',
  11 => '3',
)

*/

separate_and_flags.rb

#!/usr/bin/env ruby

flags = "001000001000"
month = %w[4 5 6 7 8 9 10 11 12 1 2 3]

combo = []
month.each_index do |key|
  suffix = flags[key, 1] == "1" ? '月期' : nil  
  combo << "#{month[key]} #{suffix}"
end

puts combo

=begin

$ ruby separate_and_flags.rb
4
5
6 月期
7
8
9
10
11
12 月期
1
2
3

=end