Related
if File.exist?("restaurant.txt") then
newfile=File.open("restaurant.txt","r")
lines=newfile.readlines
i=0
while i<lines.size
item=lines[i]
i+=1
quantity=lines[i].to_i
i+=1
price=lines[i].to_i
i+=1
sub=quantity*price
puts sub
end
end
I am trying to move the sub values into an array
Just create an array and push the values.
array = Array.new
if File.exist?("restaurant.txt") then
newfile = File.open("restaurant.txt","r")
lines = newfile.readlines
i=0
while i < lines.size
item = lines[i]
i += 1
quantity = lines[i].to_i
i += 1
price = lines[i].to_i
i += 1
sub = quantity*price
#puts sub
array.push(sub)
end
puts array.to_s
end
Using File#readlines, array slicing, array deconstruction, and asserting a precondition instead of using an if statement, this code can be simplified as follows:
#!/usr/bin/env ruby
FILENAME = 'restaurant.txt'
raise "#{FILENAME} does not exist" unless File.file?(FILENAME)
lines = File.readlines(FILENAME).map(&:chomp)
subs = lines.each_slice(3).map do |slice|
_item, quantity, price = slice
_item = _item.to_i # _item is unused, but this is here for completeness
quantity = quantity.to_i
price = price.to_f
quantity * price
end
p subs
Also, price, and maybe even quantity should be a floating point number and not an integer.
I have built a version of mastermind that checks a user's input and provides feedback based on how close the user's guess was to the winning sequence. If you're not familiar with the game, you get feedback indicating how many of your characters were guessed correctly at the same index and how many characters guessed are in the sequence, but at the wrong index. If there are duplicates in the guess, then you would not count the extra values unless they correspond to the same number of duplicates in the secret code.
Example: If the sequence is ["G","G","G","Y"] and the user guesses ["G", "Y","G","G"] then you'd want to return 2 for items at the same index and 2 for items at different indexes that are included in the secret sequence.
Another example: If the sequence is ["X","R","Y","T"] and the user guesses ["T","T","Y","Y"] then you'd return 1 for items at the same index 1 for the character guessed that is in the sequence but at the wrong index.
Anyway, to me this is not a simple problem to solve. Here's the code I used to get it to work, but it's not elegant. There must be a better way. I was hoping someone can tell me what I'm missing here?? New to Ruby...
def index_checker(input_array, sequence_array)
count = 0
leftover_input = []
leftover_sequence = []
input.each_with_index do |char, idx|
if char == sequence[idx]
count += 1
else
leftover_input << char
leftover_sequence << sequence[idx]
end
end
diff_index_checker(leftover_input, leftover_sequence, count)
end
def diff_index_checker(input, sequence, count)
count2 = 0
already_counted = []
input.each do |char|
if sequence.include?(char) && !already_counted.include?(char)
count2 += 1
already_counted << char
end
end
[count, count2]
end
Here's a clean Ruby solution, written in idiomatic Ruby object-oriented style:
class Mastermind
def initialize(input_array, sequence_array)
#input_array = input_array
#sequence_array = sequence_array
end
def matches
[index_matches, other_matches]
end
def results
[index_matches.size, other_matches.size]
end
private
attr_reader :input_array, :sequence_array
def index_matches
input_array.select.with_index { |e, i| e == sequence_array[i] }
end
def other_matches
non_exact_input & non_exact_sequence
end
def non_exact_input
array_difference(input_array, index_matches)
end
def non_exact_sequence
array_difference(sequence_array, index_matches)
end
# This method is based on https://stackoverflow.com/a/3852809/5961578
def array_difference(array_1, array_2)
counts = array_2.inject(Hash.new(0)) { |h, v| h[v] += 1; h }
array_1.reject { |e| counts[e] -= 1 unless counts[e].zero? }
end
end
You would use this class as follows:
>> input_array = ["G","G","G","Y"]
>> sequence_array = ["G", "Y","G","G"]
>> guess = Mastermind.new(input_array, sequence_array)
>> guess.results
#> [2, 2]
>> guess.matches
#> [["G", "G"], ["G", "Y"]]
Here's how it works. First everything goes into a class called Mastermind. We create a constructor for the class (which in Ruby is a method called initialize) and we have it accept two arguments: input array (the user guess), and sequence array (the answer).
We set each of these arguments to an instance variable, which is indicated by its beginning with #. Then we use attr_reader to create getter methods for #input_array and #sequence_array, which allows us to get the values by calling input_array and sequence_array from any instance method within the class.
We then define two public methods: matches (which returns an array of exact matches and an array of other matches (the ones that match but at the wrong index), and results (which returns a count of each of these two arrays).
Now, within the private portion of our class, we can define the guts of the logic. Each method has a specific job, and each is named to (hopefully) help a reader understand what it is doing.
index_matches returns a subset of the input_array whose elements match the sequence_array exactly.
other_matches returns a subset of the input_array whose elements do not match the sequence_array exactly, but do match at the wrong index.
other_matches relies on non_exact_input and non_exact_sequence, each of which is computed using the array_difference method, which I copied from another SO answer. (There is no convenient Ruby method that allows us to subtract one array from another without deleting duplicates).
Code
def matches(hidden, guess)
indices_wo_match = hidden.each_index.reject { |i| hidden[i] == guess[i] }
hidden_counts = counting_hash(hidden.values_at *indices_wo_match)
guess_counts = counting_hash(guess.values_at *indices_wo_match)
[hidden.size - indices_wo_match.size, guess_counts.reduce(0) { |tot, (k, cnt)|
tot + [hidden_counts[k], cnt].min }]
end
def counting_hash(arr)
arr.each_with_object(Hash.new(0)) { |s, h| h[s] += 1 }
end
Examples
matches ["G","G","G","Y"], ["G", "Y","G","G"]
#=> [2, 2]
matches ["X","R","Y","T"] , ["T","T","Y","Y"]
#=> [1, 1]
Explanation
The steps are as follows.
hidden = ["G","G","G","Y"]
guess = ["G", "Y","G","G"]
Save the indices i for which hidden[i] != guess[i].
indices_wo_match = hidden.each_index.reject { |i| hidden[i] == guess[i] }
#=> [1, 3]
Note that the number of indices for which the values are equal is as follows.
hidden.size - indices_wo_match.size
#=> 2
Now compute the numbers of remaining elements of guess that pair with one of the remaining values of hidden by having the same value. Begin by counting the numbers of instances of each unique element of hidden and then do the same for guess.
hidden_counts = counting_hash(hidden.values_at *indices_wo_match)
#=> {"G"=>1, "Y"=>1}
guess_counts = counting_hash(guess.values_at *indices_wo_match)
#=> {"Y"=>1, "G"=>1}
To understand how counting_hash works, see Hash::new, especially the explanation of the effect of providing a default value as an argument of new. In brief, if a hash is defined h = Hash.new(3), then if h does not have a key k, h[k] returns the default value, here 3 (the hash is not changed).
Now compute the numbers of matches of elements of guess that were not equal to the value of hidden at the same index and which pair with an element of hidden that have the same value.
val_matches = guess_counts.reduce(0) do |tot, (k, cnt)|
tot + [hidden_counts[k], cnt].min
end
#=> 2
Lastly, return the values of interest.
[hidden.size - indices_wo_match.size, val_matches]
#=> [2, 2]
In the code presented above I have substituted out the variable val_matches.
With Ruby 2.4+ one can use Enumerable#sum to replace
guess_counts.reduce(0) { |tot, (k, cnt)| tot + [hidden_counts[k], cnt].min }
with
guess_counts.sum { |k, cnt| [hidden_counts[k], cnt].min }
def judge(secret, guess)
full = secret.zip(guess).count { |s, g| s == g }
semi = secret.uniq.sum { |s| [secret.count(s), guess.count(s)].min } - full
[full, semi]
end
Demo:
> judge(["G","G","G","Y"], ["G","Y","G","G"])
=> [2, 2]
> judge(["X","R","Y","T"], ["T","T","Y","Y"])
=> [1, 1]
A shorter alternative, though I find it less clear:
full = secret.zip(guess).count(&:uniq!)
I prefer my other answer for its simplicity, but this one would be faster if someone wanted to use this for arrays larger than Mastermind's.
def judge(secret, guess)
full = secret.zip(guess).count { |s, g| s == g }
pool = secret.group_by(&:itself)
[full, guess.count { |g| pool[g]&.pop } - full]
end
Demo:
> judge(["G","G","G","Y"], ["G","Y","G","G"])
=> [2, 2]
> judge(["X","R","Y","T"], ["T","T","Y","Y"])
=> [1, 1]
I have a number of ranges that I want merge together if they overlap. The way I’m currently doing this is by using Sets.
This is working. However, when I attempt the same code with a larger ranges as follows, I get a `stack level too deep (SystemStackError).
require 'set'
ranges = [Range.new(73, 856), Range.new(82, 1145), Range.new(116, 2914), Range.new(3203, 3241)]
set = Set.new
ranges.each { |r| set << r.to_set }
set.flatten!
sets_subsets = set.divide { |i, j| (i - j).abs == 1 } # this line causes the error
puts sets_subsets
The line that is failing is taken directly from the Ruby Set Documentation.
I would appreciate it if anyone could suggest a fix or an alternative that works for the above example
EDIT
I have put the full code I’m using here:
Basically it is used to add html tags to an amino acid sequence according to some features.
require 'set'
def calculate_formatting_classes(hsps, signalp)
merged_hsps = merge_ranges(hsps)
sp = format_signalp(merged_hsps, signalp)
hsp_class = (merged_hsps - sp[1]) - sp[0]
rank_format_positions(sp, hsp_class)
end
def merge_ranges(ranges)
set = Set.new
ranges.each { |r| set << r.to_set }
set.flatten
end
def format_signalp(merged_hsps, sp)
sp_class = sp - merged_hsps
sp_hsp_class = sp & merged_hsps # overlap regions between sp & merged_hsp
[sp_class, sp_hsp_class]
end
def rank_format_positions(sp, hsp_class)
results = []
results += sets_to_hash(sp[0], 'sp')
results += sets_to_hash(sp[1], 'sphsp')
results += sets_to_hash(hsp_class, 'hsp')
results.sort_by { |s| s[:pos] }
end
def sets_to_hash(set = nil, cl)
return nil if set.nil?
hashes = []
merged_set = set.divide { |i, j| (i - j).abs == 1 }
merged_set.each do |s|
hashes << { pos: s.min.to_i - 1, insert: "<span class=#{cl}>" }
hashes << { pos: s.max.to_i - 0.1, insert: '</span>' } # for ordering
end
hashes
end
working_hsp = [Range.new(7, 136), Range.new(143, 178)]
not_working_hsp = [Range.new(73, 856), Range.new(82, 1145),
Range.new(116, 2914), Range.new(3203, 3241)]
sp = Range.new(1, 20).to_set
# working
results = calculate_formatting_classes(working_hsp, sp)
# Not Working
# results = calculate_formatting_classes(not_working_hsp, sp)
puts results
Here is one way to do this:
ranges = [Range.new(73, 856), Range.new(82, 1145),
Range.new(116, 2914), Range.new(3203, 3241)]
ranges.size.times do
ranges = ranges.sort_by(&:begin)
t = ranges.each_cons(2).to_a
t.each do |r1, r2|
if (r2.cover? r1.begin) || (r2.cover? r1.end) ||
(r1.cover? r2.begin) || (r1.cover? r2.end)
ranges << Range.new([r1.begin, r2.begin].min, [r1.end, r2.end].max)
ranges.delete(r1)
ranges.delete(r2)
t.delete [r1,r2]
end
end
end
p ranges
#=> [73..2914, 3203..3241]
The other answers aren't bad, but I prefer a simple recursive approach:
def merge_ranges(*ranges)
range, *rest = ranges
return if range.nil?
# Find the index of the first range in `rest` that overlaps this one
other_idx = rest.find_index do |other|
range.cover?(other.begin) || other.cover?(range.begin)
end
if other_idx
# An overlapping range was found; remove it from `rest` and merge
# it with this one
other = rest.slice!(other_idx)
merged = ([range.begin, other.begin].min)..([range.end, other.end].max)
# Try again with the merged range and the remaining `rest`
merge_ranges(merged, *rest)
else
# No overlapping range was found; move on
[ range, *merge_ranges(*rest) ]
end
end
Note: This code assumes each range is ascending (e.g. 10..5 will break it).
Usage:
ranges = [ 73..856, 82..1145, 116..2914, 3203..3241 ]
p merge_ranges(*ranges)
# => [73..2914, 3203..3241]
ranges = [ 0..10, 5..20, 30..50, 45..80, 50..90, 100..101, 101..200 ]
p merge_ranges(*ranges)
# => [0..20, 30..90, 100..200]
I believe your resulting set has too many items (2881) to be used with divide, which if I understood correctly, would require 2881^2881 iterations, which is such a big number (8,7927981983090337174360463368808e+9966) that running it would take nearly forever even if you didn't get stack level too deep error.
Without using sets, you can use this code to merge the ranges:
module RangeMerger
def merge(range_b)
if cover?(range_b.first) && cover?(range_b.last)
self
elsif cover?(range_b.first)
self.class.new(first, range_b.last)
elsif cover?(range_b.last)
self.class.new(range_b.first, last)
else
nil # Unmergable
end
end
end
module ArrayRangePusher
def <<(item)
if item.kind_of?(Range)
item.extend RangeMerger
each_with_index do |own_item, idx|
own_item.extend RangeMerger
if new_range = own_item.merge(item)
self[idx] = new_range
return self
end
end
end
super
end
end
ranges = [Range.new(73, 856), Range.new(82, 1145), Range.new(116, 2914), Range.new(3203, 3241)]
new_ranges = Array.new
new_ranges.extend ArrayRangePusher
ranges.each do |range|
new_ranges << range
end
puts ranges.inspect
puts new_ranges.inspect
This will output:
[73..856, 82..1145, 116..2914, 3203..3241]
[73..2914, 3203..3241]
which I believe is the intended output for your original problem. It's a bit ugly, but I'm a bit rusty at the moment.
Edit: I don't think this has anything to do with your original problem before the edits which was about merging ranges.
I have the following code for an assignment. After much debugging I found what was happening
class Integer
def initialize()
#ans = ""
end
def ans
#ans = ""
end
def ans=(value)
#ans = value
end
def to_base(base)
# convert given number into the base
# figure out how to make it the most efficient
num = self
r = 0
loop do
r = num % base # modulus
#ans = r.to_s + #ans.to_s # add to answer
num /= base # division
break unless num != 0
end
english = #ans # return value
end
def to_oct
self.to_base(8)
end
end
puts 8.to_oct
puts 8.to_base(2)
Output:
10
100010
The output for the binary version should be 1000 not 100010
What it did was append the first instance of the class 8.to_oct onto the second call 8.to_base(2)
Is there a way to have this cleared as I want to use the same number (8) in this example and convert it to various base numbers. what am I doing wrong in my class?
Thanks!
I need to group numbers that are in numerical order from an array.
(using ruby 1.9.2, rails 3.2)
Example1:
[1,2,4,5,6]
Example2:
[1,3,4,6,7]
Example3:
[1,2,3,5,6]
Example4:
[1,2,4,5,7]
After grouping
Example1:
[[1,2],[4,5,6]]
Example2:
[[1],[3,4],[6,7]]
Example3:
[[1,2,3],[5,6]]
Example4:
[[1,2],[4,5],[7]]
You get the idea.
(What I'm actually doing is grouping days, not relevant though)
Thanks in advance!
I'm not sure what you'd call this operation, but it's a sort of grouping method based on the last element processed. Something like:
def groupulate(list)
list.inject([ ]) do |result, n|
if (result[-1] and result[-1][-1] == n - 1)
result[-1] << n
else
result << [ n ]
end
result
end
end
The Enumerable module provides a large number of utility methods for processing lists, but inject is the most flexible by far.
Perfect problem to use inject (aka reduce) with:
def group_consecutive(arr)
arr.inject([[]]) do |memo, num|
if memo.last.count == 0 or memo.last.last == num - 1
memo.last << num
else
memo << [ num ]
end
memo
end
end
See it run here: http://rubyfiddle.com/riddles/0d0a5
a = [1,2,4,5,7]
out = []
a.each_index do |i|
if out.last and out.last.last == a[i]-1
out.last << a[i]
else
out << [a[i]]
end
end
puts out.inspect