Take input from a text file & output the response to a new text file

char_count.rb

# Open the source file & store each element in an array 
# (sans the newline character)
def parse_file(file)
  arr = []
  list = File.open(file)
  list.each do |item| 
    if item.include? "\n"
      arr << item.chomp
    else
      arr << item
    end
  end
  arr
end

# Return array of letter and number pairs split at underscore
# Called in get_count
def split_(elem)
  pos = elem.index('_')
  letter = elem[0..pos - 1]
  num = elem[pos + 1..-1].to_i
  [letter, num]
end

# Populate a new hash with letters while counting and math-ing
# Called in get_count
def checker(new_hash, key, value = 1)
  if new_hash[key]
    new_hash[key] += value
  else
    new_hash[key] = value
  end
end

# Make the math while placing pairs into a hash
def get_count(arr)
  hash_start = {}
  arr.each do |elem|
    if elem.include? '_'
      letter = split_(elem)[0]
      num = split_(elem)[1]
      checker(hash_start, letter, num)
    else
      checker(hash_start, elem)
    end
  end
  hash_start
end

# Split hashes into two: one with a count of 1, one with a count of more than 1
def sort_hash(almost_ready_hash)
  multi_hash = {}
  single_hash = {}
  almost_ready_hash.each do |k, v|
    if v > 1
      multi_hash[k] = v
    else
      single_hash[k] = v
    end
  end
  [multi_hash, single_hash]
end

# Sort the hashes for final presentation
def present(hashes)
  final_hash = {}
  hashes[0].sort_by{ |k, v| v}.reverse.each do |k, v|
    final_hash[k] = v
  end
  hashes[1].each do |k, v|
    final_hash[k] = v
  end
  final_hash.to_a
end

# Save the response to a new text file
def write_file(file, input)
  File.open(file, "a") do |f| 
    input.each do |e| 
      f.write("#{e[0]} #{e[1]}\n")
    end
  end
end

parsed = parse_file('list.txt')
counted = get_count(parsed)
sorted = sort_hash(counted)
write_file('new.txt', present(sorted))