trouble appending hash value ruby - ruby

Question

I'm writing a program which takes input, stores it as a hash and sorts the values.
I'm having trouble comparing a current hash value with a variable.
Sample Input:
3
A 1
B 3
C 5
A 2
B 7
C 2
Sample Output:
A 1 2
B 3 7
C 2 5
Everything works apart from this part, and I'm unsure why.
if values.key?(:keys)
if values[keys] >= val
values.store(keys,val.prepend(val + " "))
else
values.store(keys,val.concat(" " + val))
end
else
values.store(keys,val)
end
i = i + 1
end
Rest of code:
#get amount of records
size = gets.chomp
puts size
size = size.to_i
values = Hash.new(0)
i = 0
while i < (size * 2)
text = gets.chomp
#split string and remove space
keys = text.split[0]
val = text.split[1]
#check if key already exists,
# if current value is greater than new value append new value to end
# else put at beginning of current value
if values.key?(:keys)
if values[keys] >= val
values.store(keys,val.prepend(val + " "))
else
values.store(keys,val.concat(" " + val))
end
else
values.store(keys,val)
end
i = i + 1
end
#sort hash by key
values = values.sort_by { |key, value| key}
#output hash values
values.each{|key, value|
puts "#{key}:#{value}"
}
Could anyone help me out? It would be most appreciated.

Answer 1

The short answer is that there are two mistakes in your code. Here is the fixed version:
if values.key?(keys)
if values[keys] >= val
values.store(keys,values[keys].prepend(val + " "))
else
values.store(keys,values[keys].concat(" " + val))
end
else
values.store(keys,val)
end
The if statement was always evaluating as false, because you were looking for hash key named :keys (which is a Symbol), not the variable you've declared named keys.
Even with that fixed, there was a second hidden bug: You were storing a incorrect new hash value. val.concat(" " + val) would give you results like A 2 2, not A 1 2, since it's using the new value twice, not the original value.
With that said, you code is still very confusing to read... Your variables are size, i, text, val, values, key and keys. It would have been a lot easier to understand with clearer variable names, if nothing else :)
Here is a slightly improved version, without changing the overall structure of your code:
puts "How may variables to loop through?"
result_length = gets.chomp.to_i
result = {}
puts "Enter #{result_length * 2} key-value pairs:"
(result_length * 2).times do
input = gets.chomp
input_key = input.split[0]
input_value = input.split[1]
#check if key already exists,
# if current value is greater than new value append new value to end
# else put at beginning of current value
if result.key?(input_key)
if result[input_key] >= input_value
result[input_key] = "#{input_value} #{result[input_key]}"
else
result[input_key] = "#{result[input_key]} #{input_value}"
end
else
result[input_key] = input_value
end
end
#sort hash by key
result.sort.to_h
#output hash result
result.each{|key, value|
puts "#{key}:#{value}"
}

Answer 2

h = Hash.new { |h,k| h[k] = [] }
input = ['A 1', 'B 3', 'C 5', 'A 2', 'B 7', 'C 2'].join("\n")
input.each_line { |x| h[$1] << $2 if x =~ /^(.*?)\s+(.*?)$/ }
h.keys.sort.each do |k|
puts ([k] + h[k].sort).join(' ')
end
# A 1 2
# B 3 7
# C 2 5

Answer 3

This would be a more Ruby-ish way to write your code :
input = "A 1
B 3
C 5
A 2
B 7
C 2"
input.scan(/[A-Z]+ \d+/)
.map{ |str| str.split(' ') }
.group_by{ |letter, _| letter }
.each do |letter, pairs|
print letter
print ' '
puts pairs.map{ |_, number| number }.sort.join(' ')
end
#=>
# A 1 2
# B 3 7
# C 2 5