Sorting array with multiple variables - ruby

Question

I am trying to create a program where by the user can enter multiple names. those names are then displayed under each other in alphabetical order, and print(display) every second name backwards. i have gone through several tutorials this is my second day using ruby.. here is what i have so far.
name_list = {}
puts 'please enter names seperated by a space:'
name_list = gets.chomp
names = name_list.split(" ")
to grab names...
names.sort do |a,b| a.upcase <=> b.upcase end
display = "#{names}"
for ss in 0...display.length
print ss, ": ", display[ss], "\n"
end
to arrange them alphabetically and under each other.
i am really struggling to mesh it all together i think i have got at least half a dozen errors in here...if i am on the wrong path could someone guide me to some info so i can start again??
EDIT
i also had this idea of using a class.
but i would have to program the names in i wanted the user to be able to add info via the consol.
class A
def initialize(name)
#name = name
end
def to_s
#name.reverse
end
end
>> a = [A.new("greg"),A.new("pete"),A.new("paul")]
>> puts a

Answer 1

Problems in your code:
name_list defined as an empty hash at the top but not used.
split(" ") -> split
sort { |a, b| a.method <=> b.method } -> sort_by { |x| x.method } -> sort_by(&:method)
sort is not an in-place operation, assign the result (or directly use it).
display = "#{names}" -> display = names
for ss in 0...display.length -> enumerable.each_with_index { |item, index| ... }
don't write do/end in one-liners, use { ... }
I'd write:
puts 'Please enter names separated by spaces'
gets.split.sort_by(&:upcase).each_with_index do |name, index|
puts "%s: %s" % [index, (index % 2).zero? ? name : name.reverse]
end

Answer 2

A few pointers then:
names.sort do |a,b| a.upcase <=> b.upcase end # Will not modify the "names" array, but will return a sorted array.
names.sort! do |a,b| a.upcase <=> b.upcase end # Will modify the "names" array.
To display your names:
names.each_with_index do |name, index|
if index % 2 == 0
puts name
else
puts name.reverse
end
end

Answer 3

puts 'please enter names seperated by a space`enter code here` :'
names = gets.chomp.split(" ")
names.sort! {|a,b| a.upcase <=> b.upcase } # For a single line use {..} instead of do..end
names.each_with_index do |n,i|
if i % 2 == 0
p n
else
p n.reverse
end
end
You can also use a ternary operator, I used the full if else block for readability in this case.
names.each_with_index do |n,i|
p (i % 2 == 0) ? n : n.reverse
end
EDIT
command = ""
names = []
while command != "exit"
puts 'please enter names seperated by a space`enter code here` :'
command = gets.chomp!
if command == "display"
names.sort! {|a,b| a.upcase <=> b.upcase } # For a single line use {..} instead of do..end
names.each_with_index do |n,i|
if i % 2 == 0
p n
else
p n.reverse
end
end
else
names << command
end
end