Sorting an array using the numeric value of strings it contains

Question

I have a file called highscore.txt which will be read into the program and put into an array. The problem is that I can not sort the array because the points in the .txt file are read as strings, not as integers... how can I fix this?

highscore.txt:

$Nico,11\nLuis,7...$

Code:

@Bestenliste.each do |stat|
  @sorted = @sorted + [stat.to_s.split(",")]
end
@sorted = @sorted.sort {|a,b| a[1] <=> b[1]}
@sorted.each do |stat2|
  puts stat2[0].to_s + " | " + stat2[1].to_s
end

With stat.to_s.split I split one line (Nico,10) into two objects but the 10 will be a string so I can't sort the array anymore.

And yes I'm doing this in quite a complicated way since I'm new to Ruby. ^^

You can get your above code working by just modifying this line @sorted.sort {|a,b| a[1] <=> b[1]} to @sorted.sort {|a,b| a[1].to_i <=> b[1].to_i}. While you can follow @avlazarov's answer as he is correct on that. But if you just want your exiting code to work then you can do the above — Pramod Solanky
– Pramod Solanky, Commented Dec 4, 2014 at 14:44

Uri Agassi · Accepted Answer · 2014-12-04 14:59:20Z

1

array.sort_by(&:to_i) - will sort the array by calling #to_i for every string, and return an array of the scores still in strings array.map(&:to_i).sort - same but will return an array of ints

Edit: Or use to_f instead of to_i if the scores are floats

edited Dec 4, 2014 at 14:59

Uri Agassi

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answered Dec 4, 2014 at 14:08

avl

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2 Comments

Splinti Over a year ago

Won't that turn the whole array into integer? I just want the numbers to be converted

avl Over a year ago

Then just array.map(&to_f), where the array holds your string values of the score

Ajedi32 · Accepted Answer · 2014-12-04 16:10:52Z

0

The simplest way to do this is to convert the convert the strings to integers before comparing them. In the code you posted, this would be as simple as appending a .to_i to the values you are comparing in the line the sorts the array:

@sorted = @sorted.sort {|a,b| a[1].to_i <=> b[1].to_i}

As you seem to have realized though, Ruby is a pretty powerful language. There are much more readable, compact ways of doing what you did. For example, a program which does what you described could easily be implemented in one or two lines:

highscores = File.readlines('highscore.txt').map{|line| line.split(',') }
puts highscores.sort_by{|_, score| score.to_i}.map{|pair| pair.join(" | ")}

answered Dec 4, 2014 at 16:10

Ajedi32

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Comments

Uri Agassi · Accepted Answer · 2014-12-04 14:57:57Z

0

You can convert the strings to a different type. Possibly Integer or Float..

For this file:

look at this snippet from irb:

1.9.3-p194 :016 > File.readlines('test.txt').each do |line|
1.9.3-p194 :017 >   puts "#{line} - #{line.class}"
1.9.3-p194 :018?>   puts "#{line.to_i} - #{line.to_i.class}"
1.9.3-p194 :019?>   puts "#{line.to_f} - #{line.to_f.class}"
1.9.3-p194 :020?>   end
75.89 - String
75 - Fixnum
75.89 - Float
87.23 - String
87 - Fixnum
87.23 - Float
81.98 - String
81 - Fixnum
81.98 - Float
99.40 - String
99 - Fixnum
99.4 - Float
45.81 - String
45 - Fixnum
45.81 - Float

edited Dec 4, 2014 at 14:57

Uri Agassi

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answered Dec 4, 2014 at 14:17

Jason Mcmunn

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