Passing nill value to custom method - ruby

Can you please tell me why it is passing nil to check method? I am getting error main.rb:5:in `check': undefined method `%' for nil:NilClass (NoMethodError)
my_array = Array.new
$output = String.new
def check(n)
if n%3 == 0
$output = $output + 'Pop '
elsif n.even?
$output = $output + 'Crackle '
elsif n.odd?
$output = $output + 'Snap '
end
end
for x in 1..6
my_array[x] = gets.chomp.to_i
end
my_array.each { |x| check(x) }
puts $output.my_array

The reason you are getting a nil in the beginning of the array is that you are manually setting the keys in the array which creates a hole since arrays are 0 indexed in Ruby:
ary = Array.new
ary[1] = "a"
ary[2] = "b"
ary[3] = "c"
# => [nil, "a", "b", "c"]
While you could salvage this code with:
my_array = Array.new
$output = String.new
def check(n)
if n%3 == 0
$output = $output + 'Pop '
elsif n.even?
$output = $output + 'Crackle '
elsif n.odd?
$output = $output + 'Snap '
end
end
for x in 0..5
my_array[x] = gets.chomp.to_i
end
my_array.each { |x| check(x) }
puts $output.my_array
A more idiomatically correct way to write this in Ruby is:
str = 5.times.map do
n = gets.chomp.to_i
if n%3 == 0
'Pop'
elsif n.even?
'Crackle'
elsif n.odd?
'Snap'
end
end.join(" ")
puts str
for String.new and Array.new are rarely used if ever used. Use blocks instead of methods unless you're planning to reuse it later. In Ruby you can use the methods from Enumerable to both iterate over and transform arrays, hashes, ranges and other types of objects so there rarely is a reason to iterate and modify an external variable like in other languages.

With for x in 0..5 you would then have
t.rb:21:in `<main>': undefined method `my_array' for "":String (NoMethodError)
because my_array is not a method that you can send to $output.
There are many ways to do the same thing in Ruby.
my_array = []
def check(n)
case
when n % 3 == 0
'Pop'
when n.even?
'Crackle'
when n.odd?
'Snap'
else 'boom !' # not necessary in this particular case
end
end
(1..6).each do | i |
print "#{i} Enter a number > "
my_array << gets.to_i
end
puts my_array.collect { |e| check(e) }.join(' ')
Execution :
$ ruby t.rb
1 Enter a number > 44
2 Enter a number > 66
3 Enter a number > 30494
4 Enter a number > 383849
5 Enter a number > 2234
6 Enter a number > 4333
Crackle Pop Crackle Snap Crackle Snap
Don't use global variables, like $output. In the ancient (imperative programming style) languages, it was a common bug to inadvertently modify a variable accessible from anywhere.
The object oriented paradigm has been invented to isolate variables (encapsulated in an
object) to make it more difficult to modify them accidentally.
You could have use an instance variable :
#output = ''
if n%3 == 0
#output << 'Pop '
but beeing defined in the special 'main' object, it is not protected against unwanted access.
chomp is not necessary before to_i, see this post
Use iterators instead of loops. for is imperative style (C, Java), which imposes you to manage
the begin and end indexes. In an object oriented language, you simply send an iterate message to a
collection object, which takes cares of the internal details.
if and case are expressions which return the last computed value. check() returns that value.
Your my_array.each { |x| check(x) } mutates the variable $output and returns no result. In a big program, a later maintenance could insert some processing that modifies $output before you use it (bug).
The functional programming paradigm (Scala, Elixir, Kotlin) tends to use immutable variables and use functions to transform data.
The new my_array.collect { |e| check(e) }.join(' ') iterates over my_array, transforms each element calling the function check(), produces a new (immutable) collection with these transformed elements, which is then transformed by the function join() to produce the final result.

You have
for x in 1..6
my_array[x] = gets.chomp.to_i
end
Which populates the array from indexes 1 through 6, all arrays begin at index 0 so, in your method
my_array.each { |x| check(x) }
The .each method will iterate through each element of the array, starting at 0, which in this case would be nil because you never assigned a value to that index, you could change your range to
for x in 0..6
my_array[x] = gets.chomp.to_i
end
And that would work, remember to use 2 dots and not 3, as
0..6
0...6
are different, the first one is inclusive, the second one is exclusive.
You can check up more about ranges here

Related

How to get the returned value from a method from within the method?

I've been practicing some algorithms with ruby for a while, and I'm wondering if it is possible to catch the returned value from within the method.
the code below is to reverse a string without any kind of reverse method and with few local variables...
def rev(a)
i = -1
a.split("").each do |el|
el[0] = a[i]
i = i + (-1)
end.join
end
Note that the result of the 'each' method is not being assigned to any variable. So, 'each' evaluates to an array with a reversed sequence of characters. At the 'end' (literally) I've just 'called' the method 'join' to glue everything together. The idea is to 'catch' the returned value from all this process and check if is true or false that the reversed string is a palindrome.
If the reversed string is equal to the original one then the word is a palindrome. Ex. "abba", "sexes", "radar"...
for example:
def rev(a)
i = -1
a.split("").each do |el|
el[0] = a[i]
i = i + (-1)
end.join
# catch here the returned value from the code above
# and check if its a palindrome or not. (true or false)
end
Thank you guys! I will be very grateful if anyone could help me figure out this!
Just add == a to see if your reversal matches the original string:
def rev(a)
i = -1
a.split("").each do |el|
el[0] = a[i]
i = i + (-1)
end.join == a
end
puts rev("racecar") # => true
puts rev("racecars") # => false
An easier way to check palindromes (rev could be better named palindrome?) is a == a.reverse since .reverse is essentially what your split/each/join does.
If you want back all the information, you can return an array with both the values:
def rev(a)
i = -1
rev = a.split("").each do |el|
el[0] = a[i]
i = i + (-1)
end.join
[rev, rev == a] # or
# return rev, rev == a
end
p rev("abra") #=> ["arba", false]
p rev("abba") #=> ["abba", true]
You can also return a hash:
{ reverse: rev, palindrome: rev == a}
to get
#=> {:reverse=>"arba", :palindrome=>false}
#=> {:reverse=>"abba", :palindrome=>true}
Here are a couple of other ways you could reverse a string.
#1
def esrever(str)
s = str.dup
(str.size/2).times { |i| s[i], s[-1-i] = s[-1-i], s[i] }
s
end
esrever("abcdefg")
#=> "gfedcba"
esrever("racecar")
#=> "racecar"
This uses parallel assignment (sometimes called multiple assignment).
#2
def esrever(str)
a = str.chars
''.tap { |s| str.size.times { s << a.pop } }
end
esrever("abcdefg")
#=> "gfedcba"
esrever("racecar")
#=> "racecar"
I've used Object#tap merely to avoid creating a local variable initialized to an empty string and then having to make that variable the last line of the method.
With both methods a string str is a palindrome if and only if str == esrever(str).

Ruby merge duplicates in string

If I have a string like this
str =<<END
7312357006,1.121
3214058234,3456
7312357006,1234
1324958723,232.1
3214058234,43.2
3214173443,234.1
6134513494,23.2
7312357006,11.1
END
If a number in the first value shows up again, I want to add their second values together. So the final string would look like this
7312357006,1246.221
3214058234,3499.2
1324958723,232.1
3214173443,234.1
6134513494,23.2
If the final output is an array that's fine too.
There are lots of ways to do this in Ruby. One particularly terse way is to use String#scan:
str = <<END
7312357006,1.121
3214058234,3456
7312357006,1234
1324958723,232.1
3214058234,43.2
3214173443,234.1
6134513494,23.2
7312357006,11.1
END
data = Hash.new(0)
str.scan(/(\d+),([\d.]+)/) {|k,v| data[k] += v.to_f }
p data
# => { "7312357006" => 1246.221,
# "3214058234" => 3499.2,
# "1324958723" => 232.1,
# "3214173443" => 234.1,
# "6134513494" => 23.2 }
This uses the regular expression /(\d+),([\d.]+)/ to extract the two values from each line. The block is called with each pair as arguments, which are then merged into the hash.
This could also be written as a single expression using each_with_object:
data = str.scan(/(\d+),([\d.]+)/)
.each_with_object(Hash.new(0)) {|(k,v), hsh| hsh[k] += v.to_f }
# => (same as above)
There are likewise many ways to print the result, but here are a couple I like:
puts data.map {|kv| kv.join(",") }.join("\n")
# => 7312357006,1246.221
# 3214058234,3499.2
# 1324958723,232.1
# 3214173443,234.1
# 6134513494,23.2
# or:
puts data.map {|k,v| "#{k},#{v}\n" }.join
# => (same as above)
You can see all of these in action on repl.it.
Edit: Although I don't recommend either of these for the sake of readability, here's more just for kicks (requires Ruby 2.4+):
data = str.lines.group_by {|s| s.slice!(/(\d+),/); $1 }
.transform_values {|a| a.sum(&:to_f) }
...or, to going straight to a string:
puts str.lines.group_by {|s| s.slice!(/(\d+),/); $1 }
.map {|k,vs| "#{k},#{vs.sum(&:to_f)}\n" }.join
Since repl.it is stuck on Ruby 2.3: Try it online!
You could achieve this using each_with_object, as below:
str = "7312357006,1.121
3214058234,3456
7312357006,1234
1324958723,232.1
3214058234,43.2
3214173443,234.1
6134513494,23.2
7312357006,11.1"
# convert the string into nested pairs of floats
# to briefly summarise the steps: split entries by newline, strip whitespace, split by comma, convert to floats
arr = str.split("\n").map(&:strip).map { |el| el.split(",").map(&:to_f) }
result = arr.each_with_object(Hash.new(0)) do |el, hash|
hash[el.first] += el.last
end
# => {7312357006.0=>1246.221, 3214058234.0=>3499.2, 1324958723.0=>232.1, 3214173443.0=>234.1, 6134513494.0=>23.2}
# You can then call `to_a` on result if you want:
result.to_a
# => [[7312357006.0, 1246.221], [3214058234.0, 3499.2], [1324958723.0, 232.1], [3214173443.0, 234.1], [6134513494.0, 23.2]]
each_with_object iterates through each pair of data, providing them with access to an accumulator (in this the hash). By following this approach, we can add each entry to the hash, and add together the totals if they appear more than once.
Hope that helps - let me know if you've any questions.
def combine(str)
str.each_line.with_object(Hash.new(0)) do |s,h|
k,v = s.split(',')
h.update(k=>v.to_f) { |k,o,n| o+n }
end.reduce('') { |s,kv_pair| s << "%s,%g\n" % kv_pair }
end
puts combine str
7312357006,1246.22
3214058234,3499.2
1324958723,232.1
3214173443,234.1
6134513494,23.2
Notes:
using String#each_line is preferable to str.split("\n") as the former returns an enumerator whereas the latter returns a temporary array. Each element generated by the enumerator is line of str that (unlike the elements of str.split("\n")) ends with a newline character, but that is of no concern.
see Hash::new, specifically when a default value (here 0) is used. If a hash has been defined h = Hash.new(0) and h does not have a key k, h[k] returns the default value, zero (h is not changed). When Ruby encounters the expression h[k] += 1, the first thing she does is expand it to h[k] = h[k] + 1. If h has been defined with a default value of zero, and h does not have a key k, h[k] on the right of the equality (syntactic sugar1 for h.[](k)) returns zero.
see Hash#update (aka merge!). h.update(k=>v.to_f) is syntactic sugar for h.update({ k=>v.to_f })
see Kernel#sprint for explanations of the formatting directives %s and %g.
the receiver for the expression reduce('') { |s,kv_pair| s << "%s,%g\n" % kv_pair } (in the penultimate line), is the following hash.
{"7312357006"=>1246.221, "3214058234"=>3499.2, "1324958723"=>232.1,
"3214173443"=>234.1, "6134513494"=>23.2}
1 Syntactic sugar is a shortcut allowed by Ruby.
Implemented this solution as hash was giving me issues:
d = []
s.split("\n").each do |line|
x = 0
q = 0
dup = false
line.split(",").each do |data|
if x == 0 and d.include? data then dup = true ; q = d.index(data) elsif x == 0 then d << data end
if x == 1 and dup == false then d << data end
if x == 1 and dup == true then d[q+1] = "#{'%.2f' % (d[q+1].to_f + data.to_f).to_s}" end
if x == 2 and dup == false then d << data end
x += 1
end
end
x = 0
s = ""
d.each do |val|
if x == 0 then s << "#{val}," end
if x == 1 then s << "#{val}\n ; x = 0" end
x += 1
end
puts(s)

How should I refactor this conditional code in ruby?

How to refactor this function?
def split_description(first_n)
description_lines = description.split "\n"
line_num = description_lines.length
if line_num > first_n
#description_first = to_html(description_lines[0..first_n].join("\n"))
#description_remain = to_html(description_lines[first_n + 1..line_num].join("\n"))
elsif line_num > 1
#description_first = to_html(description_lines[0..first_n].join("\n"))
#description_remain = ''
else
#description_first = ''
#description_remain = ''
end
end
I am a Ruby starter and encounter this rubocup warning: Method has too many lines. [13/10]
The following is whole code url:
https://github.com/RubyStarts3/YPBT-app/blob/master/views_objects/video_info_view.rb
Code
def split_description(description, first_n)
#description_first, #description_remain =
case description.count("\n")
when 0..first_n
[description, '']
else
partition_description(description, first_n)
end.map(&:to_html)
end
def partition_description(description, first_n)
return ['', description] if first_n.zero?
offset = 0
description.each_line.with_index(1) do |s,i|
offset += s.size
return [description[0,offset], description[offset..-1]] if i == first_n
end
end
I've assumed to_html('') #=> '', but if that's not the case the modification is straightforward.
Example
So that we can see the effect of to_html, let's define it thusly.
def to_html(description)
description.upcase
end
description =<<_
It was the best of times
it was the worst of times
it was the age of wisdom
it was the age of fools
_
split_description(description, 0)
#description_first
#=> ""
#description_remain
#=> "IT WAS THE BEST OF TIMES\n..WORST OF TIMES\n..AGE OF WISDOM\n..AGE OF FOOLS\n"
split_description(description, 1)
#description_first
#=> "IT WAS THE BEST OF TIMES\n"
#description_remain
#=> "IT WAS THE WORST OF TIMES\n..AGE OF WISDOM\n..AGE OF FOOLS\n"
split_description(description, 2)
#description_first
#=> "IT WAS THE BEST OF TIMES\nIT WAS THE WORST OF TIMES\n"
#description_remain
#=> "IT WAS THE AGE OF WISDOM\nIT WAS THE AGE OF FOOLS\n"
split_description(description, 3)
#description_first
#=> "IT WAS THE BEST OF TIMES\n..WORST OF TIMES\n..AGE OF WISDOM\n"
#description_remain
#=> "IT WAS THE AGE OF FOOLS\n"
split_description(description, 4)
#description_first
#=> "IT WAS THE BEST OF TIMES\n..WORST OF TIMES\n..AGE OF WISDOM\n..AGE OF FOOLS\n"
#description_remain
#=> ""
Explanation
Firstly, is appears that description is a local variable holding a string. If so, it must be an argument of the method (along with first_n).
def split_description(description, first_n)
We want to assign values to two instance variables, so let's begin by writing
#description_first, #description_remain =
There are really two steps: obtaining the desired strings and then mapping them with to_html. So let's first concentrate on the first step.
We will now condition on the number of lines in the string
case description.count("\n")
First, let's deal with the case where the string contains no newlines
when 0
[description, '']
If the string is empty this will be ['', '']; otherwise it will contain a single string without a newline.
Next, suppose the number of newlines in the string is between 1 and first_n. In this case #description_first is to be the entire string and #description_remain is to be empty.
when 1..first_n
[description, '']
As both when 0 and when 1..first_n return the same two-element array, we can combine them:
when 0..first_n
[description, '']
To get this far, first_n is less than the number of newlines. I've used another method for the case where the number of newlines is greater than first_n.
else
partition_description(description, first_n)
partition_description simply determines the offset into description of the first_nth newline, and then partitions the string accordingly.
Lastly, we need to end the case statement, map the array of two strings returned with to_html and end the method
end.map(&:to_html)
end
As I mentioned earlier, I've assumed to_html('') #=> ''. That seems to me to be the best place do deal with empty strings.
Note that I've dealt with the string directly, rather than splitting the string into lines, manipulating the lines and then rejoining them.
Since it's used or blanked in every condition, initialize the instance variables to blank.
def split_description(first_n)
description_lines = description.split "\n"
line_num = description_lines.length
#description_first = ''
#description_remain = ''
if line_num > first_n
#description_first = to_html(description_lines[0..first_n].join("\n"))
#description_remain = to_html(description_lines[first_n + 1..line_num].join("\n"))
elsif line_num > 1
#description_first = to_html(description_lines[0..first_n].join("\n"))
end
end
I'd also move the logic for description_lines[first_n + 1..line_num].join("\n") to a method like to_html( whatever_that_is( lines, from, to) ) or the like. Then it's not so bad if you repeat the same call and the name will describe what it's doing.
If first_n is always greater than 1 I think you can modify a little the Schwern's answer:
...
#description_first = to_html(description_lines[0..first_n].join("\n")) if line_num > 1
if line_num > first_n
#description_remain = to_html(description_lines[first_n + 1..line_num].join("\n"))
end
end
This should work :
def split_description(description, first_n = 0)
lines = description.each_line
#description_first = to_html(lines.take(first_n).join)
#description_remain = to_html(lines.drop(first_n).join)
end
take and drop replace all your logic, because, as #Cary Swoveland mentionned in a comment :
if you take too much, you end up with the complete array, without error message
if you drop too much, you end ud with an empty array, without error message
Example :
[1,2].take(99) #=> [1, 2]
[1,2].drop(99) #=> []
Also each_line outputs an Array of Strings, with newlines still present. No split, chomp or join("\n") is needed.

changing integers into words ruby without gems

I am trying to change numbers up to 100 from integers into words, but have run into some trouble, can anyone point out what is missing with my code:
def in_words(integer)
numWords = {
0=>"zero",
1=>"one",
2=>"two",
3=>"three",
4=>"four",
5=>"five",
6=>"six",
7=>"seven",
8=>"eight",
9=>"nine",
10=>"ten",
11=>"eleven",
12=>"twelve",
13=>"thirteen",
14=>"fourteen",
15=>"fifteen",
16=>"sixteen",
17=>"seventeen",
18=>"eighteen",
19=>"nineteen",
20=>"twenty",
30=>"thirty",
40=>"fourty",
50=>"fifty",
60=>"sixty",
70=>"seventy",
80=>"eighty",
90=>"ninety",
100=>"one hundred"
}
array = integer.to_s.split('')
new_array = []
numWords.each do |k,v|
array.each do |x|
if x = k
new_array.push(v)
end
end
end
new_array.join('')
end
Right now when I do:
inwords(0)
I get the following:
=>"zeroonetwothreefourfivesixseveneightnineteneleventwelvethirteenfourteenfiftee nsixteenseventeeneighteennineteentwentythirtyfourtyfiftysixtyseventyeightyninetyone hundred"
Edit
I noticed your code iterates through the array a lot of times and uses the = instead of the == in your if statements.
Your code could be more efficient using the Hash's #[] method in combination with the #map method.., here's a one-line alternative:
integer.to_s.split('').map {|i| numWords[i.to_i]} .join ' '
Also, notice that the integer.to_s.split('') will split the array into one-digit strings, so having numbers up to a hundred isn't relevant for the code I proposed.
To use all the numbers in the Hash, you might want to use a Regexp to identify the numbers you have. One way is to do the following (I write it in one line, but it's easy to break it down using variable names for each step):
integer.to_s.gsub(/(\d0)|([1]?\d)/) {|v| v + " "} .split.map {|i| numWords[i.to_i]} .join ' '
# or:
integer.to_s.gsub(/(#{numWords.keys.reverse.join('|')})/) {|v| v + " "} .split.map {|i| numWords[i.to_i]} .join ' '
# out = integer.to_s
# out = out.gsub(/(#{numWords.keys.reverse.join('|')})/) {|v| v + " "}
# out = out.split
# out = out.map {|i| numWords[i.to_i]}
# out = out.join ' '
Edit 2
Since you now mention that you want the method to accept numbers up to a hundred and return the actual number (23 => twenty three), maybe a different approach should be taken... I would recommend that you update your question as well.
def in_words(integer)
numWords = {
0=>"zero",
1=>"one",
2=>"two",
3=>"three",
4=>"four",
5=>"five",
6=>"six",
7=>"seven",
8=>"eight",
9=>"nine",
10=>"ten",
11=>"eleven",
12=>"twelve",
13=>"thirteen",
14=>"fourteen",
15=>"fifteen",
16=>"sixteen",
17=>"seventeen",
18=>"eighteen",
19=>"nineteen",
20=>"twenty",
30=>"thirty",
40=>"fourty",
50=>"fifty",
60=>"sixty",
70=>"seventy",
80=>"eighty",
90=>"ninety",
100=>"one hundred"
}
raise "cannot accept such large numbers" if integer > 100
raise "cannot accept such small numbers" if integer < 0
return "one hundred" if integer == 100
if integer < 20 || integer %10 == 0
numWords[integer]
else
[numWords[integer / 10 * 10], numWords[integer % 10]].join ' '
end
end
the integer / 10 * 10 makes the number a round number (ten, twenty, etc') because integers don't have fractions (so, 23/10 == 2 and 2 * 10 == 20). The same could be achieved using integer.round(-1), which is probably better.
It seems like all you're trying to do is find a mapping from an implicit hash
module NumWords
INT2STR = {
0=>"zero",
1=>"one",
2=>"two",
3=>"three",
4=>"four",
5=>"five",
6=>"six",
7=>"seven",
8=>"eight",
9=>"nine",
10=>"ten",
11=>"eleven",
12=>"twelve",
13=>"thirteen",
14=>"fourteen",
15=>"fifteen",
16=>"sixteen",
17=>"seventeen",
18=>"eighteen",
19=>"nineteen",
20=>"twenty",
30=>"thirty",
40=>"fourty",
50=>"fifty",
60=>"sixty",
70=>"seventy",
80=>"eighty",
90=>"ninety",
100=>"one hundred"
}
module_function
def in_words(integer)
INT2STR[integer]
end
end
The above code separates the hash definition from the method call so that the hash doesn't get recreated every time you call in_words.
You can also use Hash#fetch instead of Hash#[] as Andrey pointed out.
Your test whether x = k is your first problem (in two ways).
Firstly, if x = k means assign the value of k to x and then execute the if block if that value is true (basically anything other than false or nil).
What you should actually be testing is x == k which will return true if x is equal to k.
The second problem is that you converted your number into an array of string representation so you are comparing, for example, if "0" == 0. This won't return true because they are different types.
If you convert it to if x.to_i == k then your if block will be executed and you'll get:
> in_words(0)
=> "zero"
Then you get to move onto the next problem which is that you're looking at your number digit by digit and some of the values you are testing against need two digits to be recognised:
> in_words(10)
=> "zeroone"
You might be in looking at a different question then - or maybe that is the question you wanted answered all along!
Here's another way you might do it:
ONES_TO_TEXT = { 0=>"zero", 1=>"one", 2=>"two", 3=>"three", 4=>"four",
5=>"five", 6=>"six", 7=>"seven", 8=>"eight", 9=>"nine" }
TEENS_TO_TEXT = { 10=>"ten", 11=>"eleven", 12=>"twelve",
13=>"thirteen", 15=>"fifteen" }
TENS_TO_TEXT = { 2=>"twenty", 3=>"thirty", 5=>"fifty", 8=>"eighty" }
def in_words(n)
raise ArgumentError, "#{n} is out-of_range" unless (0..100).cover?(n)
case n.to_s.size
when 1 then ONES_TO_TEXT[n]
when 3 then "one hundred"
else
case n
when (10..19)
TEENS_TO_TEXT.key?(n) ? TEENS_TO_TEXT[n] : ONES_TO_TEXT[n]+"teen"
else
t,o = n.divmod(10)
(TENS_TO_TEXT.key?(t) ? TENS_TO_TEXT[t] : ONES_TO_TEXT[t]+"ty") +
(o.zero? ? '' : "-#{ONES_TO_TEXT[o]}")
end
end
end
Let's try it:
in_words(5) #=> "five"
in_words(10) #=> "ten"
in_words(15) #=> "fifteen"
in_words(20) #=> "twenty"
in_words(22) #=> "twenty-two"
in_words(30) #=> "thirty"
in_words(40) #=> "fourty"
in_words(45) #=> "fourty-five"
in_words(50) #=> "fifty"
in_words(80) #=> "eighty"
in_words(99) #=> "ninety-nine"
in_words(100) #=> "one hundred"
Here the increased complexity may not be justified, but this approach may in fact simplify the calculations when the maximum permitted value of n is much greater than 100.

Values in the while loop do not modify outside values

I have a long code but I tried to copy and adapt my problem in as few lines as possible . I have a method which creates an array( 2D ) with 0 and 1
array1 = newValue(2) - the number 2 represents how many 1 the array has
array2 = newValue(3)
and this loop
(0..9).each do|i|
(0..9).each do|j|
while((array1[i][j] == array2[i][j]) && (array2[i][j] == 1)) do
array1 = newvalue(2)
array2 = newvalue(3)
end
end
end
I'm using the while loop so I won t have a 1 in the same position in both arrays . But what is inside the while loop doesn't modify the values of the array . I also tried using map!/collect! but I think I did something wrong because nothing happened. I hope you can understand what I was trying to do .
Edit:
def newValue(value)
value = value.to_i
array = Array.new(10) { Array.new(10 , 0) }
(a lot of conditions on how to position the items in the array)
return array
end
Here's my take... hopefully it'll help out. It seems that what you noticed was true. The arrays are not getting reset. Probably because inside the each blocks, the scope is lost. This is probably because the are arrays. I took a slightly different approach. Put everything in a class so you can have instance variables that you can control and you know where they are and that they are always the same.
I pulled out the compare_arrays function which just returns the coordinates of the match if there is one. If not it returns nil. Then, youre while loop is simplified in the reprocess method. If you found a match, reprocess until you don't have a match any more. I used a dummy newValue method that just returned another 2d array (as you suggested yours does). This seems to do the trick from what I can tell. Give it a whirl and see what you think. You can access the two arrays after all the processing with processor.array1 as you can see I did at the bottom.
# generate a random 2d array with 0's and val's
def generateRandomArray(val=1)
array = []
(0..9).each do |i|
(0..9).each do |j|
array[i] ||= []
array[i][j] = (rand > 0.1) ? 0 : val
end
end
array
end
array1 = generateRandomArray
array2 = generateRandomArray
def newValue(val)
generateRandomArray(val)
end
class Processor
attr_reader :array1, :array2
def initialize(array1, array2)
#array1 = array1
#array2 = array2
end
def compare_arrays
found = false
for ii in 0..9
break unless for jj in 0..9
if ((#array2[ii][jj] == 1) && (#array1[ii][jj] == 1))
found = true
break
end
end
end
[ii,jj] if found
end
def reprocess
while compare_arrays
puts "Reprocessing"
#array1 = newValue(2)
#array2 = newValue(3)
reprocess
end
end
end
processor = Processor.new(array1, array2)
processor.reprocess
puts processor.array1.inspect

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