Ruby search for the same values in multidimensional array - arrays

Question

I have an array with many arrays inside (2d) (in this example there are four of them):
[
[13, 15, 18, 23, 23, 11, 14, 19, 19, 5, 10, 10, 8, 8],
[8, 15, 19, 21, 21, 12, 16, 18, 18, 11, 13, 13, 6, 6],
[9, 15, 21, 23, 23, 7, 13, 15, 15, 12, 14, 14, 8, 8],
[2, 8, 14, 16, 16, 7, 13, 15, 15, 12, 14, 14, 8, 8]
]
I need to find if any element on any of these arrays is the same and at the same index as in other array. I need to get all those numbers and their indexes.
For ex. First_array[1] = 15, as well as second_array[1] = 15 and third_array[1] = 15. So I need these, with their indexes.
Also all needed values must come from arrays that are to the left or to the right to the array. For ex. - array_one[3] = 23, array_two[3] = 21 and array_three[3] = 23. I dont need these since array_two has a different value and it separates array_one from array_three.
And What I can get is the length of arrays (they all the same length) and the number of arrays, as variables.
I hope you got my point :)
Looks like I am abit closer to my goal. It seems this checks well for the second array (so only two first arrays being checked, but if this was done, the rest should be much easier). And do not judge me, judge just the code :D I know its ugly, its just a prototype:
array.each do |c|
c.each do |v|
c.each_with_index do |k, i|
next_array = array[i + 1]
if next_array.include? v
its_index = next_array.index(v)
if c.index(v) == its_index
p v
end
end
break
end
end
return
end

Answer 1

arr = [[13, 15, 18, 23, 23, 11, 14, 19, 19, 5, 10, 10, 8, 8],
[ 8, 15, 19, 21, 23, 12, 16, 18, 19, 11, 13, 13, 6, 8],
[ 9, 15, 21, 23, 16, 12, 13, 15, 15, 12, 14, 14, 8, 8],
[ 2, 8, 14, 21, 16, 7, 13, 15, 15, 12, 14, 14, 8, 8]]
I've modified arr in a few places.
arr.transpose.each_with_index.with_object({}) do |(col,j),h|
i = 0
h[j] = col.chunk(&:itself).each_with_object({}) do |(x,arr),g|
count = arr.size
g.update(i=>{ value: x, number: count }) if count > 1
i += count
end
end
#=> {0=>{},
# 1=>{0=>{:value=>15, :number=>3}},
# 2=>{},
# 3=>{},
# 4=>{0=>{:value=>23, :number=>2}, 2=>{:value=>16, :number=>2}},
# 5=>{1=>{:value=>12, :number=>2}}
# 6=>{2=>{:value=>13, :number=>2}},
# 7=>{2=>{:value=>15, :number=>2}},
# 8=>{0=>{:value=>19, :number=>2}, 2=>{:value=>15, :number=>2}},
# 9=>{2=>{:value=>12, :number=>2}},
# 10=>{2=>{:value=>14, :number=>2}},
# 11=>{2=>{:value=>14, :number=>2}},
# 12=>{2=>{:value=> 8, :number=>2}},
# 13=>{0=>{:value=> 8, :number=>4}}}
The keys of this hash are indices of columns of arr. The values are hashes that contain the locations and counts of all vertically-adjacent elements which appear at least twice. The columns at indices 0, 2 and 3, are the only ones that contains no vertically-adjacent duplicate values. The column at index 1 contains 3 15's beginning at row index 0; the column at index 4 contains 2 23's, beginning at row index 0 and 2 16's, beginning at row index 2.

Answer 2

matrix = [
[13, 15, 18, 23, 23, 11, 14, 19, 19, 5, 10, 10, 8, 8],
[ 8, 15, 19, 21, 21, 12, 16, 18, 18, 11, 13, 13, 6, 6],
[ 9, 15, 21, 23, 23, 7, 13, 15, 15, 12, 14, 14, 8, 8],
[ 2, 8, 14, 16, 16, 7, 13, 15, 15, 12, 14, 14, 8, 8]
]
equal_surround = matrix
.each_with_index.map do |v,i|
v.each_with_index.map do |k,j|
if (i-1>=0 && k == matrix[i-1][j])
k
elsif (i+1 < matrix.length && k == matrix[i+1][j])
k
else
nil
end
end
end
=> [
[nil, 15, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil],
[nil, 15, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil],
[nil, 15, nil, nil, nil, 7, 13, 15, 15, 12, 14, 14, 8, 8],
[nil, nil, nil, nil, nil, 7, 13, 15, 15, 12, 14, 14, 8, 8]
]

Answer 3

You didn't show any code, so I won't write any either.
I can tell you that array#transpose should make this problem much more manageable, though.
You'll just need to iterate on the rows (former columns) and look for any repeating number.
You can either do it FORTRAN style with a loop or with fancier Enumerable methods, like each_with_index, map or chunk.

Answer 4

test_array = [
[13, 15, 18, 23, 23, 11, 14, 19, 19, 5, 10, 10, 8, 8],
[8, 15, 19, 21, 21, 12, 16, 18, 18, 11, 13, 13, 6, 6],
[9, 15, 21, 23, 23, 7, 13, 15, 15, 12, 14, 14, 8, 8],
[2, 8, 14, 16, 16, 7, 13, 15, 15, 12, 14, 14, 8, 8]
]
final_res = Hash.new {|h,k| h[k] = Array.new }
test_array.each_cons(2).to_a.each_with_index do |(a,b),i|
final_match = Hash.new {|h,k| h[k] = Array.new }
res = a & b
res.each do |ele|
a_index = a.each_index.select{|i| a[i] == ele}
b_index = b.each_index.select{|i| b[i] == ele}
(a_index & b_index).size > 0 ? final_match[ele] << (a_index & b_index) : ''
end
final_match.each_value {|v| v.flatten!}
final_res[:"Match Values Between Array #{i+1} amd Array #{i+2}"] << final_match
end
final_res.each do |a|
puts a
end
OUTPUT:
Match Values Between Array 1 amd Array 2
{15=>[1]}
Match Values Between Array 2 amd Array 3
{15=>[1]}
Match Values Between Array 3 amd Array 4
{15=>[7, 8], 7=>[5], 13=>[6], 12=>[9], 14=>[10, 11], 8=>[12, 13]}