Read Input from Console in Ruby

Read input from console in Ruby?

Are you talking about gets?

puts "Enter A"
a = gets.chomp
puts "Enter B"
b = gets.chomp
c = a.to_i + b.to_i
puts c

Something like that?

Update

Kernel.gets tries to read the params found in ARGV and only asks to console if not ARGV found. To force to read from console even if ARGV is not empty use STDIN.gets

Taking input from user in console in ruby

You probably have a newline in your input you haven't stripped. When processing data from files, be sure to chomp any input values. Even better is to call strip which will remove leading and trailing spaces.

gets.chomp.split(',')

Whenever trying to do diagnostics, it's important to show "invisible" characters:

puts code_2.inspect
# "TYP\n"

This would probably have exposed the issue sooner. inspect can be misleading, though, on custom classes that have their own customized emitter. It can't always be trusted, but it's usually a good place to start.

How can I get user input from command line with this program?

ARGV is an array. You have to get its first element.

print ARGV  # An array
x = ARGV[0]
print x

With ruby filename.rb 123, ARGV is ["123"] and x is "123".

make ruby script in console keep accepting input until you're done

Yes,, you can try as something like below using while keyword :

puts "Give your inputs"

while (a = gets.chomp) != 'exit'
  puts a
end

# or use until as below
until (a = gets.chomp) =~ /(?:ex|qu)it/i
      puts a
end

While you will enter the string 'Exit'/'exit'/'Quit'/'quit' from the command prompt, your while loop will be stopped, Otherwise you will be keep prompting for the next input.

Output to console while preserving user input in ruby

The two important parts of my proposal are:

1. system("stty raw -echo") # to instantly get any typed character in combination with

2. using STDIN.getc with a string-var serving as an input-buffer to reprint the user input.

Pressing 9 (& boolean variable incoming_message) is used for ultra-simple simulation for your server-messages.

(Being more realistic would bloat the example without adding much, since you have to adapt the idea for your scenario anyway.)

Press x for exit.

Sample output:

$ ruby simultaneous_input_and_output.rb
Hello World!9
The incoming message is: true
Hello World!9x

You entered:
Hello World!9x
End!

---

#!/usr/bin/ruby

$input_buffer = "";  
incoming_message = false

begin  
  system("stty raw -echo")  

  begin   
    str = STDIN.getc  
    print str.chr  

    $input_buffer = $input_buffer + str.chr  
    if str.chr == '9'  
      incoming_message = true  
    end  
    if incoming_message   
      puts "\nThe incoming message is: " + incoming_message.to_s  
      print $input_buffer  
      incoming_message = false  
    end  
  end while (str.chr != 'x')  
ensure  
  system("stty -raw echo")  
end  

puts "\n\nYou entered:"   
puts $input_buffer  
puts "End!"    

---

P.S.:
for system("stty raw -echo") see (User Jay)
How to get a single character without pressing enter?

How do I read an input file in ruby using in command line?

I'm assuming the content of the input files will be different and you will have some logic to determine that. You can actually just read that file input as if it was entered as text by the user and do whatever you need to do with it.

Example:

test.rb

puts gets.chomp

testfile

test

Terminal

$ ruby test.rb < testfile
$ test

Program to take input from command line into an array and find the biggest among them

How about capturing the array in one line?

#!/usr/bin/ruby

puts "Enter a list of numbers"

list = gets   # Input something like "1 2 3 4" or "3, 5, 6, 1"

max = list.split.map(&:to_i).max

puts "The largest number is: #{max}"

Testing program that runs with user input from the console

As demonstrated in this answer, you can override getvalue to feed in the user input.

Here is complete code that works without actually using gets. I had to add couple of missing methods - validate_floor_number and final_destination:

require 'minitest/autorun'

class Elevator
  attr_accessor :current_floor

  def initialize
    @current_floor = 0
    @requested_floor = 0
    #@last_floor = false
  end

  def get_value
    gets.chomp
  end

  def validate_floor_number(v)
    v.to_i rescue false
  end

  def arrival
    print "Enter floor number: "
    @requested_floor = get_value

    # only proceed if user entered an integer
    if validate_floor_number(@requested_floor)
      @requested_floor = @requested_floor.to_i
      move
    else
      arrival
    end
  end

  def move
    msg = ""
    @current_floor < @requested_floor ? msg = "Going Up!" : msg = "Going Down"
    puts msg
    @current_floor = @requested_floor
    next_move
  end

  def final_destination 
    puts "Reached your floor"
  end

  def next_move
    puts "Do you want to go to another floor? Y/N"
    another_floor = (get_value).upcase
    another_floor == 'N' ? final_destination : arrival
  end

 end 

 describe "checks that the elevator can change directions" do
    before do
      class Elevator
          @@moves = [3, 'Y', 5, 'Y', 2, 'Y', 7, 'N'].each
          def get_value; @@moves.next end
      end
    end

    it "should stop on floor 7" do
      e = Elevator.new
      e.arrival
      assert_equal(e.current_floor, 7)
    end
 end

Output of above program:

Run options: --seed 2561

# Running:

Enter floor number: Going Up!
Do you want to go to another floor? Y/N
Enter floor number: Going Up!
Do you want to go to another floor? Y/N
Enter floor number: Going Down
Do you want to go to another floor? Y/N
Enter floor number: Going Up!
Do you want to go to another floor? Y/N
Reached your floor
.

Finished in 0.001334s, 749.4982 runs/s, 749.4982 assertions/s.

1 runs, 1 assertions, 0 failures, 0 errors, 0 skips
[Finished in 0.3s]

---

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