Advent of code 2023 —Day 01

def process_input(input_array)
  results = []
#設定一個空陣列

# 使用each do將陣列裡的數丟出處理並替換
  input_array.each do |input_string|
    digits = input_string.gsub(/\D/, '')
    result = "#{digits[0]}#{digits[-1]}"
#利用字串將首位數+尾數串起來，如果只有一個數字則重複
    results.push(result)
#將結果推進result裡
  end

  # 計算結果陣列中數字的總和 #利用.map(&:to_i)將陣列裡的字串轉為數字才可以相加
  sum_result = results.map(&:to_i).sum

  # 輸出結果
  puts sum_result
end

'foo'.match('f') # => #<MatchData "f">

input = <<~INPUT
two1nine
eightwothree
abcone2threexyz
xtwone3four
4nineeightseven2
zoneight234
7pqrstsixteen
INPUT

replacement = {
  "one" => "1",
  "two" => "2",
  "three" => "3",
  "four" => "4",
  "five" => "5",
  "six" => "6",
  "seven" => "7",
  "eight" => "8",
  "nine" => "9",
  "1" => "1",
  "2" => "2",
  "3" => "3",
  "4" => "4",
  "5" => "5",
  "6" => "6",
  "7" => "7",
  "8" => "8",
  "9" => "9",
  "0" => "0"
}
result = input.each_line.map do |line|
  digits = line.match(/(#{replacement.keys.join('|')})/, 0)
#匹配hash的key，並將所有keys用|(or)隔開，一個符合即可，後面的0為從最左邊最一開始匹配
  first = replacement[digits[0]]

  digits = line.reverse.match(/(#{replacement.keys.map(&:reverse).join('|')})/, 0)
  last = replacement[digits[0].reverse]
#使用反轉搜索最後一個數

  (first+last).to_i
end.sum

p result