I want to put a possibly infinite amount of numbers in and then it's added to an array, which is then all added together.
I saw this on a few other questions but they were all just puts-ing the array, not summing.
case input
when 'add'
puts "Enter the numbers to add on separate lines then hit enter on another line"
add_array = []
numbers_to_add = " "
while numbers_to_add != ""
numbers_to_add = gets.chomp
add_array.push numbers_to_add
end
add_array.delete('')
add_array.map(&:to_f).inject(:+)
puts add_array
end
You can utilize the inject method.
[1,2,3].inject(:+) #=> 6
By the looks of your code I'd guess that your incoming array is an array of strings, not an array of numbers. To convert them to decimals (floats) you can use:
sum = add_array.map(&:to_f).inject(:+)
puts sum
This applies the #to_f operation on every element, then passes that to the summing function (#inject(:+))
Related
I am trying to create something that constantly takes a users input until they say stop. Then, add all of the previous numbers together. This is what I have so far:
arr = []
puts "Give me a number:"
while input = gets.chomp
if input == "stop"
break
else
puts "Give me a number:"
arr << input
end
end
sum = arr.inject(:+)
puts sum
This is working fine up until adding the numbers together. The arr.inject(:+) seems to be joining the numbers together rather than adding.
For example, when in the while loop, I am entering 1, 2 and 3 into the gets.chomp, but the program is returning 123 rather that 6.
Where am I going wrong?
arr.inject(0) { |sum,e| sum + e.to_i }
a bit more verbose but your problem is that reading from input == String and you want Integer.
Other solution could be
arr.map(&:to_i).inject(:+)
But the first one is more efficient but less fancy.
It is the combination of
arr << input
and
arr.inject(:+)
For example, if you change the first one to:
arr << input.to_i
then it would not be wrong any more.
I have my array:
array = Array.new(10) { Array.new(10 , 0)}
Which when printed out contains a 10x10 grid of 0s.
During the programme some of the elements of the array are replaced with "."
The user then has to change all the elements which contain "." so that they contain "x".
So I'm trying to make a loop which keeps asking the user to input numbers which refer to elements until the array contains no more "."s and puts "Game Over"
Therefore I need to make a loop which keeps going until all elements of the array are not equal to "."
So this is what I came up with which doesn't work
until array != "." do
Sorry, I have very little knowledge of Ruby so my terminology isn't great.
Thank you! :)
Change the stopping condition to: array.flatten.any?{|v| v=="."} (i.e while this is true carry on with whatever)
Loop through all the elements of each subarray, changing the elements if they are equal to '.'
array.each do |subarray|
subarray.each do |e|
e = 'x' if e == '.'
end
end
I have a ruby problem
Here's what i'm trying to do
def iterate1 #define method in given class
#var3 = #var2.split(" ") #split string to array
#var4 = #var3
#var4.each do |i| #for each array item do i
ra = []
i.each_char {|d| ra << counter1(d)} # for each char in i, apply def counter1
#sum = ra.inject(:+)
#sum2 = #sum.inject(:+) #have to do the inject twice to get values
end
#sum2
I know i have over complicated this
Basically the input is a string of letters and values like "14556 this word 398"
I am trying to sum the numbers in each value, seperated by the whitespace like (" ")
When i use the def iterate1 method the block calls the counter1 method just fine, but i can only get the value for the last word or value in the string.
In this case that's 398, which when summed would be 27.
If i include a break i get the first value, which would be 21.
I'm looking to output an array with all of the summed values
Any help would be greatly appreciated
I think you're after:
"10 d 20 c".scan(/\b\d+\b/).map(&:to_i).inject(:+) # Returns 30
scan(/\b\d+\b/) will extract all numbers that are made up of digits only in an array, map(&:to_i) will convert them to integers and I guess you already know what inject(:+) will do.
I'm not sure if I understand what you're after correctly, though, so it might help if you provide the answer you expect to this input.
EDIT:
If you want to sum the digits in each number, you can do it with:
"12 d 34 c".scan(/\b\d+\b/).map { |x| x.chars.map(&:to_i).inject(:+) }
x.chars will return an enumerator for the digits, map(&:to_i) will convert them to integers and inject(:+) will sum them.
The simplest answer is to use map instead of each because the former collects the results and returns an array. e.g:
def iterate1 #define method in given class
#var3 = #var2.split(" ") #split string to array
#var4 = #var3
#var4.map do |i| #for each array item do i
ra = []
i.each_char {|d| ra << counter1(d)} # for each char in i, apply def counter1
#sum = ra.inject(:+)
#sum2 = #sum.inject(:+) #have to do the inject twice to get values
end
end
You could write it a lot cleaner though and I think Stefan was a big help. You could solve the issue with a little modification of his code
# when you call iterate, you should pass in the value
# even if you have an instance variable available (e.g. #var2)
def iterate(thing)
thing.scan(/\b\d+\b/).map do |x|
x.chars.map{|d| counter1(d)}.inject(:+)
end
end
The above assumes that the counter1 method returns back the value as an integer
I am new to Ruby and just can't figure out how you take input for an array from a user and display it.If anyone could clear that I can add my logic to find the biggest number.
#!/usr/bin/ruby
puts "Enter the size of the array"
n = gets.chomp.to_i
puts "enter the array elements"
variable1=Array.new(n)
for i in (0..n)
variable1[i]=gets.chomp.to_i
end
for i in (0..n)
puts variable1
end
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}"
You are doing it ok. But try this little change
#!/usr/bin/ruby
puts "Enter the size of the array"
n = (gets.chomp.to_i - 1)
puts "enter the array elements"
variable1=Array.new(n)
for i in (0..n)
variable1[i]=gets.chomp.to_i
end
puts variable1
or for undefined number of values here is one way
#!/usr/bin/ruby
puts "enter the array elements (type 'done' to get out)"
input = gets.chomp
arr = []
while input != 'done'
arr << input.to_i
input = gets.chomp
end
puts arr
I believe that this is a little bit more elegant solution.
puts "Please enter numbers separated by spaces:"
s = gets
a = s.split(" ")
#Displays array
puts a
#Displays max element
puts a.max
First you collect the series of numbers from the user, then you use a split method on the string, which converts it to the array. If you want to use some other separator, like "," than you can write s.split(","). After that you can use your logic to find the biggest number or you could just use max method.
Some feedback:
chomp.to_i is a bit redundant, since the latter will also remove newlines.
for x in y is not commonly seen in idiomatic Ruby code. It basically behaves like each with slightly different scoping rules and probably should have been removed from the language a while ago.
Ruby arrays are dynamic, so no need to preinitialize them. Something like (1..n).map { gets.to_i } would also produce the array you need.
Displaying it can then be done like this: array.each { |n| puts n }
Alternatively you can use the strip approach outlined before, take the numbers as command line arguments in ARGV or pipe into your program using ARGF.
A snippet of my code below flips a coin and outputs a result of 10 total heads or tails.
(e.g. Heads Tails Heads Tails...)
I'd like to store this into a variable where I can put it into an array and use its strings.
%w[act] only outputs the string "act". How can I get that line of code to output my array of strings from the line act = coin.flip?
Updated and added full code
class Coin
def flip
flip = 1 + rand(2)
if flip == 2
then puts "Heads"
else
puts "Tails"
end
end
end
array = []
10.times do
coin = Coin.new
array << coin.flip
end
puts array
This:
10.times do
coin = Coin.new
act = coin.flip
end
doesn't produce an array. It simply creates ten coin flips and throws them all away, the result of that expression is, in fact, 10. If you want an array, you'll need to build one.
You could take Douglas's approach or try something a bit more idiomatic.
The Integer#times method returns an enumerator so you can use any of the Enumerable methods on it rather than directly handing it a block. In particular, you could use collect to build an array in one nice short piece of code:
a = 10.times.collect { Coin.new.flip }
That gives you 10 flips in the Array a and then you can puts a or puts a.join(', ') or whatever you want.
The %w[] won't work because that's for generating an Array of whitespace separated words:
%w[] Non-interpolated Array of words, separated by whitespace
So %w[a b c] is just a nicer way of saying ['a', 'b', 'c'] and the words within %w[] are treated as single quoted strings rather than variables or method calls to be evaluated.
Seems that there is some editing going on. You'll also want to modify your flip method to return the flip rather than print it:
def flip
flip = 1 + rand(2)
if flip == 2
"Heads"
else
"Tails"
end
end
Then you'll get your Heads and Rails in the array.
Put the act results into an array.
arr = []
10.times do
coin = Coin.new
arr << coin.flip
end
p arr # => [...]