I'm having trouble summing an array. Here's my existing code:
pageArray = Array.new
puts "How many pages long is the book you're reading?"
pageArray << gets.chomp
puts "Are you reading any other books right now?"
yn = gets.chomp
while yn != "no" do
puts "How many pages long is your next book?"
pageArray << gets.chomp
puts "Are you reading any other books right now?"
yn = gets.chomp
end
pageSum = pageArray.reduce(:+)
puts pageSum
When I go through and enter the values 100 and 50, the final return is "10050," rather than "150." Am I missing something obvious?
The code could be written more clearly, and more Ruby-like. Here's some untested code that is more idiomatic:
page_array = []
puts "How many pages long is the book you're reading?"
page_array << gets.chomp
loop do
puts 'Are you reading any other books right now?'
yn = gets.chomp.downcase
break if yn == 'no'
puts 'How many pages long is your next book?'
page_array << gets.chomp.to_i
end
page_sum = page_array.reduce(:+)
puts page_sum
Notice:
variables in Ruby are in snake_case, notInCamelCase.
loop do will loop forever. Simply break when you've received the break value.
you should fold the case of the value used as a break to catch variations in 'y' and 'Y'.
take the time to format your code so it's easily read, even for quick tests. It's amazing how often code we think is just a test actually gets put into production, so do it right the first time.
You are entering strings and concatenating them.
Use gets.chomp.to_i
You need to change the string you get from gets to an int.
pageArray << gets.chomp.to_i
Related
I have a program that displays a numbered list and asks the user to input either a number or name from the list, and loops a block until the user enters "exit", after which it ends.
I want to add a line or two that puts an error message like, "Sorry, I don't seem to understand your request" if the user inputs something that is not on the list (name/number) and is not the word "exit".
I can't seem to figure it out. Any advice? My current code is below.
def start
display_books
input = nil
while input != "exit"
puts ""
puts "What book would you more information on, by name or number?"
puts ""
puts "Enter list to see the books again."
puts "Enter exit to end the program."
puts ""
input = gets.strip
if input == "list"
display_books
elsif input.to_i == 0
if book = Book.find_by_name(input)
book_info(book)
end
elsif input.to_i > 0
if book = Book.find(input.to_i)
book_info(book)
end
end
end
puts "Goodbye!!!"
end
Seems that you should add an elsif statement in this if:
if book = Book.find_by_name(input)
book_info(book)
elsif input != 'exit'
puts "Sorry, I don't seem to understand your request"
end
A good template for an interpreter is to build around Ruby's very capable case statement:
loop do
case (gets.chomp.downcase)
when 'list'
display_books
when /\Afind\s+(\d+)/
if book = Book.find($1.to_i)
book_info(book)
end
when /\Afind\s+(.*)/
if book = Book.find_by_name($1)
book_info(book)
end
when 'exit'
break
else
puts "Not sure what you're saying."
end
end
Although this involves regular expressions, which can be a bit scary, it does give you a lot of flexibility. \A represents "beginning of string" as an anchor, and \s+ means "one or more spaces". This means you can type in find 99 and it will still work.
You can create a whole command-line interface with it if you take the time to specify the commands clearly. Things like show book 17 and delete book 17 are all possible with a bit of tinkering.
So I've been messing around with Ruby for the first time after finishing the codecademy course up to "Object Oriented Programming, Part I" and I decided to start making a calculator. For some reason though, I get this error:
calc.rb:13:in `addition': undefined local variable or method `user_input' for main:Object (NameError)
from calc.rb:21:in `<main>'
I'm confused why it doesn't see my "user_input" array. Is it out of the scope of the method? Did I initialize it wrong?
Here's the code so you can see for yourself, it's obviously nothing sophisticated and it's not finished. I'm just trying to test for addition right now.
#!/usr/bin/env ruby
user_input = Array.new
puts "Would you like to [a]dd, [s]ubtract, [m]ultiply, or [d]ivide? "
type_of_math = gets.chomp
def addition
operator = :+
puts "Please enter the numbers you want to add (enter \"=\" to stop adding numbers): "
until gets.chomp == "="
user_input << gets.chomp.to_i
end
sum = user_input.inject(operator)
return sum
end
case type_of_math
when "a"
addition
when "s"
puts "Test for subtraction"
when "m"
puts "Test for multiplication"
when "d"
puts "Test for division"
else
puts "Wrong"
end
Consider this untested variation on your code. It's more idiomatic:
def addition
user_input = []
puts 'Please enter the numbers you want to add (enter "=" to stop adding numbers): '
loop do
input = gets.chomp
break if input == '='
user_input << input
end
user_input.map(&:to_i).inject(:+)
end
Notice that it puts user_input into the method. It also uses the normal [] direct assignment of an empty array to initialize it. Rather than chomp.to_i each value as it's entered it waits to do that until after the loop exits.
Instead of while loops, consider using loop do. They tend to be more easily seen when scanning code.
Also notice there's no return at the end of the method. Ruby automatically returns the last value seen.
I am trying to see if I can create a list of user input requests with a hash in this program I am trying to create. Whats the best way to go about this?
print "would you like to begin a changeover? (y/n) "
input = gets.chomp
tracking = {
"start time" => input.Time.now,
"Type?" => input,
"shift?" => input,
"standard hrs?" => input,
"actual hrs?" => input,
"end time" => input = gets.chomp.Time.now
}
tracking.each do |key, value|
puts "great please answer the following: #{tracking}"
end
thanks in advance!
You have to remember that the evaluation is sequential, going from top to bottom (unless you are defining functions/methods). In your code:
You ask the user about a changeover
You get user input (say, y) into the variable input
You make a hash, with six values; four of them will contain y, two of them will contain current time
You iterate over the hash, printing its values (and asking the user nothing).
Or at least it would if gets.chomp.Time.now was not an error.
So, taking care about the timing:
print "would you like to begin a changeover? (y/n) "
unless gets.chomp.tolower == 'n'
puts "great please answer the following:"
tracking = {
"start time" => Time.now
}
[
"Type?",
"shift?",
"standard hrs?",
"actual hrs?"
].each do |question|
print question
tracking[question] = gets.chomp
}
tracking["end_time"] = Time.now
end
Thanks Alot! This set me on the right track. However, was not time stamping the beginning and end of the questionnaire the way I wanted. After playing with the code a bit on my own however, I was able to make it work.
print "would you like to begin a changeover? (y/n) "
unless gets.chomp. == "n"
puts Time.now
puts "great please answer the following: "
end
questionnaire = ["Type", "Shift?", "Standard hrs?", "Actual hrs?"]
.each do |question|
puts question
questionnaire = gets.chomp
end
puts "Please type 'done' when change over complete"
input = gets.chomp
puts Time.now
I can't get this program to respond properly to user input. Various looping techniques either only run the block once or run the block infinitely no matter what the user inputs (I've tried case and while as well). Here's the most recent method I've tried:
work_summary = []
begin
# code that runs a sprint and adds results to the work_summary array
puts "Would you like to add a sprint, Y/N?"
sprint = gets.to_s
end until sprint == "N"
print work_summary, "\n"
Ruby never objects to my syntax with any of the various methods, but it also never works.
You need
sprint = gets.chomp
gets returns string with trailing "\n".
http://web.njit.edu/all_topics/Prog_Lang_Docs/html/ruby/syntax.html#begin
Begin is typically used for exception handling. I think you're looking for a while loop.
Here is an example
work_summary = []
while true
puts "Would you like to add a sprint?"
sprint = gets.chomp
if sprint == "N"
break
elsif sprint == "Y"
puts "What's your time?"
time = gets.chomp
work_summary << time
else
puts "I didn't understand your request. Enter Y or N"
end
end
I found two possibility over here which is suitable for you
First one is
while true
puts "Would you like to add a sprint?"
sprint = gets.chomp
if sprint == "N"
break
elsif sprint == "Y"
puts "What's your time?"
time = gets.chomp
work_summary << time
else
puts "Wrong request. Enter Y or N"
end
end
Here Lopp will run until break Doesn't get executed
Second thing you can Modify 1 Line in your code which is
sprint = gets.chomp
this will extract last special character of your string which is generated by gets and work fine in your case
Ruby noob here learning the ropes. I'm currently going through this tutorial and am working on this exercise:
Let's write a program which asks us to
type in as many words as we want (one
word per line, continuing until we
just press Enter on an empty line),
and which then repeats the words back
to us in alphabetical order.
I'm ignoring the alphabetical order part, for now.
Here is my code:
puts 'Hi, do you need something sorted?'
yn = gets.chomp
while yn != 'no'
puts 'What else?'
array = [gets]
yn = gets.chomp
end
puts 'Here\'s what you told me: ' +array.to_s
I've tweaked this for a few hours. To prevent my laptop from breaking due to an act of frustration I'm taking a break. Can anybody with more experience, and possibly more patience, point out my errors?
Keep in mind that every time you gets is a method that asks the user for input. On your lines:
array = [gets]
yn = gets.chomp
You are actually asking for input twice. Instead, store the user input somewhere (such as the array, see below) and get the stored value rather than asking the user twice.
Further, array = [gets] replaces the existing array with an array containing one element (the user input). You are never building up user input into the array. Instead, initialize the array before the while loop and use << in the loop:
array = Array.new
...
while yn != "no"
...
array << gets.chomp
yn = array.last
...
end
If you're having difficulty with something, the first thing you should do is try something simpler.
Rather than doing gets and looping, just try doing a simple gets.
puts 'Hi, do you need something sorted?'
yn = gets.chomp
Then I'd see if yn was what I expected.
The next thing I'd do is, rather than doing a loop many times, just try it once
puts 'Hi, do you need something sorted?'
yn = gets.chomp
if yn != 'no'
puts 'What else?'
array = [gets]
yn = gets.chomp
STDERR.puts "array is #{array.inspect}"
STDERR.puts "yn is #{yn.inspect}"
end
Then you'd hopefully realize that array and yn are both getting input, which wouldn't make sense.
For more hints on how to debug Ruby code, see How do I debug Ruby scripts?
I was having the same problem. Here is where I ended up (I think it meets all the specifications from the question):
puts 'Type in as many words as you\'d like. When you\'re finished, press enter on an empty line'
array = []
input = ' '
while input != ''
input = gets.chomp
array.push input
end
puts
puts array.sort
while yn != "no"
array << yn
print "What else? "
yn = gets.chomp
end
The "<<" appends yn to your array. (The only reason I used print is because it puts the cursor right next to the question mark instead of on the next line. No other reason)
#encoding:utf-8
x = Array.new
puts "enter something:".capitalize
y = ''
while y !=#nill
y = gets.chomp
x.push y
end
x.delete ('')
x.compact
puts "You entered: " + x.sort.to_s
puts "Objects in array: " + x.size.to_s
#made by ~Pick#chu!!!
Another way to read ‘Arrays’ from the console could be:
1: print “enter the values: ”
2: a = gets.chomp # input: “tom mark rosiel suresh albert”
3: array = a.split(‘ ‘) # .split() method return an array
4: p array # ["tom, "mark, "rosiel", "suresh", "albert"]
now, lets say you want an array of integers, all you have to do is:
# input “1 2 3 4 5″
3: array = a.split(‘ ‘).map{ |value| value.to_i }
4: p array # [1, 2, 3, 4, 5]
the clue here is to use a standard separator in order to use the .split() function.
here is how I've done this program:
array = [ ]
input = gets.chomp
while
input != ''
array.push input
input = gets.chomp
end
puts array
puts
puts array.sort