So this may seem odd, and I have done quite a bit of googling, however, I am not really a programmer, (sysops) and trying to figure out how to pass data to the AWS API in the required format, which does seem a little odd.
So, working with resources in AWS, I need to pass tags which are keys and values. The key is a string. The value is a comma separated string, in the first element of an array. So in Ruby terms, looks like this.
{env => ["stage,qa,dev"]}
and not
{env => ["stage","qa","dev"]}
I'm created an admittedly. not a very pretty little app that will allow me to run ssm documents on targeted instances in aws.
I can get the string into an array element using this class I created
class Tags
attr_accessor :tags
def initialize
#tags = {"env" => nil ,"os" => nil ,"group" => nil }
end
def set_values()
puts "please enter value/s for the following keys, using spaces or commas for multiple values"
#tags.each { |key,value|
print "enter #{key} value/s: "
#tags[key] = [gets.strip.chomp]
#tags[key] = Validate.multi_value(tags[key])
}
end
end
I then call this Validate.multi_value passing in the created Array, but it spits an array of my string value back.
class Validate
def self.multi_value(value)
if value.any?{ |sub_string| sub_string.include?(",") || sub_string.include?(" ") }
value = value[0].split(/[,\s]+/)
return value
else
return value
end
end
end
Using pry, I've seen it gets for example ["stage dev qa"] then the if statement does work, then it spits out ["stage","dev","qa"].
and I need it to output ["stage,dev,qa"] but for the life of me, I can't make it work.
I hope that's clear.
If you have any suggestions, I'd be most grateful.
I'm not hugely experienced at ruby and the may be class methods that I've missed.
If your arrays are always coming through in the format ["stage dev qa"] then first we need to split the one string into the parts we want:
arr = ["stage dev qa"]
arr.split(' ')
=> ["stage", "dev", "qa"]
Then we need to join them with the comma:
arr.split(' ').join(',')
=> "stage,dev,qa"
And finally we need to wrap it in an array:
[arr.first.split(' ').join(',')]
=> ["stage,dev,qa"]
All together:
def transform_array(arr)
[arr.first.split(' ').join(',')]
end
transform_array(['stage dev qa'])
=> ['stage,dev,qa']
More info: How do I convert an array of strings into a comma-separated string?
I see no point in creating a class here when a simple method would do.
def set_values
["env", "os", "group"].map do |tag|
puts "Please enter values for #{tag}, using spaces or commas"
print "to separate multiple values: "
gets.strip.gsub(/[ ,]+/, ',')
end
end
Suppose, when asked, the user enters, "stage dev,qa" (for"env"), "OS X" (for"OS") and "Hell's Angels" for "group". Then:
set_values
#=> ["stage,dev,qa", "OS,X", "Hell's,Angels"]
If, as I suspect, you only wish to convert spaces to commas for "env" and not for "os" or "group", write:
def set_values
puts "Please enter values for env, using spaces or commas"
print "to separate multiple values: "
[gets.strip.gsub(/[ ,]+/, ',')] +
["os", "group"].map do |tag|
print "Please enter value for #{tag}: "
gets.strip
end
end
set_values
#=> ["stage,dev,ga", "OS X", "Hell's Angels"]
See Array#map, String#gsub and Array#+.
gets.strip.gsub(/[ ,]+/, ',') merely chains the two operations s = gets.strip and s.gsub(/[ ,]+/, ','). Chaining is commonplace in Ruby.
The regular expression used by gsub reads, "match one or more spaces or commas", [ ,] being a character class, requiring one of the characters in the class be matched, + meaning that one or more of those spaces or commas are to be matched. If the string were "a , b,, c" there would be two matches, " , " and ",, "; gsub would convert both to a single comma.
Using print rather than puts displays the user's entry on the same line as the prompt, immediately after ": ", rather than on the next line. That is of course purely stylistic.
Often one would write gets.chomp rather than gets.strip. Both remove newlines and other whitespace at the end of the string, strip also removes any whitespace at the beginning of the string. strip is probably best in this case.
What do you think about this?, everything gets treated in the Validates method. I don't know if you wanted to remove repeated values, but, just in case I did, so a
"this string,, has too many,,, , spaces"
will become
"this,string,has,too,many,spaces"
and not
"this,,,,string,,,has,too,,many,,,,,,spaces"
Here's the code
class Tags
attr_accessor :tags
# initializes the class (no change)
#
def initialize
#tags = {"env" => nil ,"os" => nil ,"group" => nil }
end
# request and assign the values <- SOME CHANGES
#
def set_values
puts "please enter value/s for the following keys, using spaces or commas for multiple values"
#tags.each do |key,value|
print "enter #{key} value/s: "
#tags[key] = Validate.multi_value( gets )
end
end
end
class Validate
# Sets the array
#
def self.multi_value(value)
# Remove leading spaces, then remove special chars,
# replace all spaces with commas, then remove repetitions
#
[ value.strip.delete("\n","\r","\t","\rn").gsub(" ", ",").squeeze(",") ]
end
end
EDITED, thanks lacostenycoder
I'm trying to loop this question until the user's input is a string value:
Question: What is your name?
I don't want the user to just press enter and leave the name blank.
I don't want the user's input to be numeric/numbers.
Please see my code below:
name1 = gets.chomp.to_s
loop do
print "Please enter your name "
name1 = gets.chomp.to_s
if name1.empty?
puts "No input."
else name1.to_i
puts "Illegal character ':'"
end
end
With this code, I can't proceed to the next question even if I input a string value. Please help.
Your code has several issues:
Your input and output is out of order. You gather input before prompting and that input (from your first line) is never used:
name1 = gets.chomp.to_s # <- Ruby is waiting for input
loop do
print "Please enter your name " # <- user is prompted to enter name
name1 = gets.chomp.to_s # <- previous input is overwritten
# ...
end
The first line should probably be deleted.
gets might return nil, but chomp always returns a string. Calling to_s afterwards is therefore superfluous.
Your if-else construct is actually:
if name1.empty?
puts "No input."
else
name1.to_i
puts "Illegal character ':'"
end
So whenever the input is not empty?, you convert it to an integer (discarding the result) and print an error message. You probably want an elsif instead (/.../ is a regexp and \d matches a digit):
if name1.empty?
puts 'No input.'
elsif name1.match? /\d/
puts 'Digits not allowed.'
end
You could also use a case expression:
case name1
when ''
puts 'No input.'
when /\d/
puts 'Digits not allowed.'
end
You never break out of your loop. The code keeps looping even if no error was found. This can be fixed by adding a break statement in an else branch (to either if or case):
# ...
else
break
end
gets.chomp will always return a string, and as such there is no need to call to_s on the method.
If you don't want the user to be able to input any integers, you could use the following for a clean solution:
name.count("0-9") > 0
If this returns true, then you know that the user's input contains at least one number.
So I'm trying to find the last character from user input in Ruby.
I've tried the following-
print "Enter in a string: "
user_input = gets
end_char = user_input[-1,1]
puts "#{end_char} is the last char!"
But it returns
" is the last char!".
I've tried
end_char = "test"[-1,1]
and that works as it should (returns t). But its not working when I use user input as the string instead of just typing in a string itself. Help?
So when you say "Enter in a string" and you type "foo", what's the last thing you do? Well you hit enter obviously! So what you actually capture is "foo\n".
Calling user_input[-1,1] actually gives back the \n return symbol which just prints a break return in the output.
print "Enter in a string: "
user_input = gets.chomp
end_char = user_input[-1,1]
puts "#{end_char} is the last char!"
the #chomp method actually removes the return character from the input.
Now when I run it:
stacko % ruby puts.rb
Enter in a string: hi Lupo90
0 is the last char!
Consider this IRB session:
I'll enter "foo":
irb(main):001:0> user_input = gets
foo
"foo\n"
I entered "foo", and to terminate the input I had to press Return (or Enter depending on the OS and keyboard), which is the "\n" (or "\r\n") line-ending, depending on whether your OS is *nix or Windows.
Looking at what I entered:
irb(main):002:0> user_input[-1]
"\n"
Here's what is output. Notice that the single-quotes are on separate lines because a "\n" is a new-line character:
irb(main):003:0> puts "'\n'"
'
'
nil
(The trailing nil is the result of puts and isn't important for this example.)
So, gets returned everything entered, including the trailing new-line. Let's fix that:
irb(main):004:0> user_input = gets.chomp
foo
"foo"
irb(main):005:0> user_input[-1]
"o"
irb(main):006:0> puts '"%s" is the last char' % [user_input[-1]]
"o" is the last char
chomp is used to strip trailing line-end from the end of a string:
irb(main):010:0> "foo\n".chomp
"foo"
irb(main):011:0> "foo\r\n".chomp
"foo"
This is a really common question on Stack Overflow. Perhaps searching for it would have helped?
I understand about the \n that's automatically at the end of puts and gets, and how to deal with those, but is there a way to keep the display point (the 'cursor position', if you will) from moving to a new line after hitting enter for input with gets ?
e.g.
print 'Hello, my name is '
a = gets.chomp
print ', what's your name?'
would end up looking like
Hello, my name is Jeremiah, what's your name?
You can do this by using the (very poorly documented) getch:
require 'io/console'
require 'io/wait'
loop do
chars = STDIN.getch
chars << STDIN.getch while STDIN.ready? # Process multi-char paste
break if ["\r", "\n", "\r\n"].include?(chars)
STDOUT.print chars
end
References:
http://ruby-doc.org/stdlib-2.1.0/libdoc/io/console/rdoc/IO.html#method-i-getch
http://ruby-doc.org/stdlib-2.1.0/libdoc/io/wait/rdoc/IO.html#method-i-ready-3F
Related follow-up question:
enter & IOError: byte oriented read for character buffered IO
Perhaps I'm missing something, but 'gets.chomp' works just fine does it not? To do what you want, you have to escape the apostrophe or use double-quotes, and you need to include what the user enters in the string that gets printed:
print 'Hello, my name is '
a = gets.chomp
print "#{a}, what's your name?"
# => Hello, my name is Jeremiah, what's your name?
Works for me. (Edit: Works in TextMate, not Terminal)
Otherwise, you could just do something like this, but I realise it's not quite what you were asking for:
puts "Enter name"
a = gets.chomp
puts "Hello, my name is #{a}, what's your name?"
I'm trying to look for a specific character in an array but this character is being entered by the user.
I first order the array and then ask the user to enter a specific character and then I should see if that character exists in any of the words that the array has
For some reason, if when checking for the existence of the character, I "hard code" a character, it works, but it doesn't work if I try to look for the character that the user has entered...
list = [ 'Mom' , 'Dad' , 'Brother' , 'Sister' ]
puts ("Enter the character you would like to find");
character = gets
for i in 0..(list.length - 1)
if (list[i].include?(#{character}))
puts ("Character #{character} found in the word #{list[i]}");
end
Thanks a lot!
It is because gets adds a \n to the end of the string. Use gets.chomp! so you can get rid of the last char.
You should use "chomp" to get rid of the carriage return at the end of the line of the input. In addition you could condense your code as well.
list = [ 'Mom' , 'Dad' , 'Brother' , 'Sister' ]
puts ("Enter the character you would like to find");
character = gets.chomp
list.each do |e|
puts "Character #{character} found in the word #{e}" if e.include?(character)
end