What is the difference between using MESSAGE and tags for the last string?
user = ARGV.first
prompt = '> '
puts "Hi #{user}, im the #{$0} script."
puts "I'd like to ask you a few questions."
puts "Do you like me #{user}?"
print prompt
likes = STDIN.gets.chomp()
puts "Where do you live #{user}?"
print prompt
lives = STDIN.gets.chomp()
puts "What kind of computer do u have?"
print prompt
computer = STDIN.gets.chomp()
puts <<MESSAGE
"Alright, so you said #{likes} about liking me. You live in #{lives}. Not sure where it is.
And you have a #{computer} computer, which is nice."
MESSAGE
What you see is something called here-docs. It's a convenient way to have multiline strings without having to escape quotes. Besides this, they are just regular strings.
Some editors may offer additional features. See my other answer about this.
Related
I am trying to make a console program that asks the user for their name, and greets them. I am coding in Notepad++, and running it in the git bash console. My code is:
puts "Hello, please type in your name: "
name = gets.chomp
puts "Hello #{name}, it is a pleasure to meet you!"
When it runs, it waits for user input, and once that is entered, it prints:
Hello, please type in your name:
Hello <name_the_user_entered>, it is a pleasure to meet you!
Even though the user prompt is first in the code, it accepts user input before any test is printed. Am I missing something?
Ruby might be buffering output. To force it, use flush:
$stdout.puts "Hello, please type in your name: "
$stdout.flush
name = gets.chomp
puts "Hello #{name}, it is a pleasure to meet you!"
But I think in newer Ruby versions, this shouldn't be necessary.
I can't get this to work with the Start Command Prompt with Ruby on windows.
I got this simple programm:
puts "Whats your name?"
name = gets
puts "Hello" + name + ". How are you?"
But if I call it with "ruby program.rb", instead for waiting for my input, it just prints out:
Whats your name?
Helloputs "Whats your name?"
. How are you?
It is like the "gets" command is not been recognized. Why does this happen?
It looks like you are (somehow) passing the name of your programm two times on the command line. Your described behavior is reproducible when you are running
ruby program.rb program.rb
This works the way it does since gets does not read from STDIN in all cases. Instead, it prefers to read the files mentioned on the command line first. Only if there is no additional file on the command line, gets falls back to read from STDIN
The question on why you are passing the filename of your ruby program twi times is unfortunately less clear. If you are not calling it that way on your own, this might be caused by some strange environment options in your shell or due to your Ruby setup.
I was curious as well, and found this link How does gets and gets.chomp in ruby work?
Apparently it created a new line therefore could not find the name.
This seemed to work, (following the instructions in the link)
puts "Whats your name?"
name = gets
puts "Hello " + name.chomp + ". How are you?"
Have fun.
Also if you start using rails, you can also test in your console
Example
> def test1
> ...code ..
> end
> test1
#Ray Ban I have used your code
puts "Whats your name?"
name = gets
puts "Hello" + name + ". How are you?"
in gets.rb file and run it using $ ruby gets.rb and it worked as expected.
I am using ruby-2.3.0
I so decided to make a palindrome program, but I did so by checking a string inputted by a user. In order to do this properly, I wanted to strip away the capitalization, spaces, and punctuation. I managed to get everything but the punctuation part of it working. Every time I try with a string like "Madam, I'm Adam" the program crashes. I am very new to Ruby, and I have only learned my knowledge through the Codecademy website. And I also using the editor provided to run my code. Every time I run it like:
puts "Enter a string!"
user_input = gets.chomp
user_input.downcase!
user_input = user_input.gsub(/[^0-9a-z ]/i, '')
if user_input.include?(" ")
user_input.gsub!(/ /, "")
end
if user_input == user_input.reverse
print "Is a pallindrome"
else
print "Is not a pallindrome"
end
It crashes. But if I run it like:
puts "Enter a string!"
user_input = gets.chomp
user_input.downcase!
if user_input.include?(" ")
user_input.gsub!(/ /, "")
end
if user_input == user_input.reverse
print "Is a pallindrome"
else
print "Is not a pallindrome"
end
It works. What a I doing wrong here? Why does my program always crash when I attempt to take away the punctuation?
Nothing is wrong with your program. Codecademy has a bug reading any input that has a quote in it...
Try it out:
gets
Just enter ' to see it crash...
My advice is to get your own local environment to develop on ruby. There are many many resources out there to help you install a simple ruby environment on any OS.
After that, download and install Sublime Text and start creating your ruby source file. Then you will see that ruby <your_file>.rb will work perfectly as you expect.
Are they the same, or are there subtle differences between the two commands?
gets will use Kernel#gets, which first tries to read the contents of files passed in through ARGV. If there are no files in ARGV, it will use standard input instead (at which point it's the same as STDIN.gets.
Note: As echristopherson pointed out, Kernel#gets will actually fall back to $stdin, not STDIN. However, unless you assign $stdin to a different input stream, it will be identical to STDIN by default.
http://www.ruby-doc.org/core-1.9.3/Kernel.html#method-i-gets
gets.chomp() = read ARGV first
STDIN.gets.chomp() = read user's input
If your color.rb file is
first, second, third = ARGV
puts "Your first fav color is: #{first}"
puts "Your second fav color is: #{second}"
puts "Your third fav color is: #{third}"
puts "what is your least fav color?"
least_fav_color = gets.chomp
puts "ok, i get it, you don't like #{least_fav_color} ?"
and you run in the terminal
$ ruby color.rb blue yellow green
it will throw an error (no such file error)
now replace 'gets.chomp' by 'stdin.gets.chomp' on the line below
least_fav_color = $stdin.gets.chomp
and run in the terminal the following command
$ ruby color.rb blue yellow green
then your program runs!!
Basically once you've started calling ARGV from the get go (as ARGV is designed to) gets.chomp can't do its job properly anymore. Time to bring in the big artillery: $stdin.gets.chomp
because
if there is stuff in ARGV, the default gets method tries to treat the first one as a file and read
from that. To read from the user's input (i.e., stdin) in such a situation, you have to use
it STDIN.gets explicitly.
Often I find myself doing the following:
print "Input text: "
input = gets.strip
Is there a graceful way to do this in one line? Something like:
puts "Input text: #{input = gets.strip}"
The problem with this is that it waits for the input before displaying the prompt. Any ideas?
I think going with something like what Marc-Andre suggested is going to be the way to go, but why bring in a whole ton of code when you can just define a two line function at the top of whatever script you're going to use:
def prompt(*args)
print(*args)
gets
end
name = prompt "Input name: "
Check out highline:
require "highline/import"
input = ask "Input text: "
One liner hack sure. Graceful...well not exactly.
input = [(print 'Name: '), gets.rstrip][1]
I know this question is old, but I though I'd show what I use as my standard method for getting input.
require 'readline'
def input(prompt="", newline=false)
prompt += "\n" if newline
Readline.readline(prompt, true).squeeze(" ").strip
end
This is really nice because if the user adds weird spaces at the end or in the beginning, it'll remove those, and it keeps a history of what they entered in the past (Change the true to false to not have it do that.). And, if ARGV is not empty, then gets will try to read from a file in ARGV, instead of getting input. Plus, Readline is part of the Ruby standard library so you don't have to install any gems. Also, you can't move your cursor when using gets, but you can with Readline.
And, I know the method isn't one line, but it is when you call it
name = input "What is your name? "
Following #Bryn's lead:
def prompt(default, *args)
print(*args)
result = gets.strip
return result.empty? ? default : result
end
The problem with your proposed solution is that the string to be printed can't be built until the input is read, stripped, and assigned. You could separate each line with a semicolon:
$ ruby -e 'print "Input text: "; input=gets.strip; puts input'
Input text: foo
foo
I found the Inquirer gem by chance and I really like it, I find it way more neat and easy to use than Highline, though it lacks of input validation by its own.
Your example can be written like this
require 'inquirer'
inputs = Ask.input 'Input text'