Question

I am doing a simple selection sort in ruby but I am sorting in descending order. It’s confusing me because this work for all of my data except for one number.

def parallel_sort(data, labels)
    raise "unequal array lengths" if  data.length != labels.length
    temp = File.open("temp.txt", "w")
    0.upto(data.length - 2) do |i|
        max = i # largest value
        (i+1).upto(data.length - 1) { |j| max = j if data[j] > data[max] } 
        data[i], data[max], labels[i], labels[max] = data[max], data[i], labels[max], labels[i] if i != max 

        temp.puts "->", data, "\n", labels, "\n"
    end

    return [data, labels]
end

unsorted data:

->
26.71%
0.17%
0.65%
0.36%
0.17%
2.79%
0.04%
18.03%
0.13%
25.7%
25.18%
0.36%

Iterations:

->
26.71%
25.7%
0.65%
0.36%
0.17%
2.79%
0.04%
18.03%
0.13%
0.17%
25.18%
0.36%

->
26.71%
25.7%
25.18%
0.36%
0.17%
2.79%
0.04%
18.03%
0.13%
0.17%
0.65%
0.36%

18.03% gets skipped here:

->
26.71%
25.7%
25.18%
2.79%
0.17%
0.36%
0.04%
18.03%
0.13%
0.17%
0.65%
0.36%

->
26.71%
25.7%
25.18%
2.79%
18.03%
0.36%
0.04%
0.17%
0.13%
0.17%
0.65%
0.36%

->
26.71%
25.7%
25.18%
2.79%
18.03%
0.65%
0.04%
0.17%
0.13%
0.17%
0.36%
0.36%

->
26.71%
25.7%
25.18%
2.79%
18.03%
0.65%
0.36%
0.17%
0.13%
0.17%
0.04%
0.36%

->
26.71%
25.7%
25.18%
2.79%
18.03%
0.65%
0.36%
0.36%
0.13%
0.17%
0.04%
0.17%

->
26.71%
25.7%
25.18%
2.79%
18.03%
0.65%
0.36%
0.36%
0.17%
0.13%
0.04%
0.17%

->
26.71%
25.7%
25.18%
2.79%
18.03%
0.65%
0.36%
0.36%
0.17%
0.17%
0.04%
0.13%`

->
26.71%
25.7%
25.18%
2.79%
18.03%
0.65%
0.36%
0.36%
0.17%
0.17%
0.13%`
0.04%

I can’t figure out why 2.79% gets counted as > 18.03%

Any help would be great, Thanks!

Answer 1

Seems like you are sorting alphabetically so I would wager the data you are sorting are strings when you wanted them to be floats.