Parse string to Int

parse_int.rb

def number_map
  {
      "0" => 0,
      "1" => 1,
      "2" => 2,
      "3" => 3,
      "4" => 4,
      "5" => 5,
      "6" => 6,
      "7" => 7,
      "8" => 8,
      "9" => 9
  }
end

def parse_int(str)
  return 0 if str.nil?
  str.strip!
  return 0 if str.empty?
  indices = (0 ... str.length).find_all { |i| str[i] == '.' }
  return 0 if indices.size > 1
  str = str[0...indices[0]] unless indices.empty?
  result = 0
  multiplier = 10 ** (str.size - 1)
  sign = 1
  if str[0] == "-"
    sign = -1
    str = str[1..-1]
  end
  str.chars.each do |c|
    return 0 unless val = number_map[c]
    result += val * multiplier
    multiplier /= 10
  end
  result * sign
end

what happens if you pass?

"4.3"
"132213214282020324392311201238123093113401382340923892349342923482829"
"-0"
"3.222223213131131313131"
"0.000000000003"

Code updated. Now will return 0 for invalid cases (as per Ruby behavior for similar function).
For floats, will return the integer part before the period.