How to break up an array into sub arrays?

Question

I am trying to manipulate an array of arrays, in such a way that I have access to each individual array as a variable.

In my code I am storing 7 different entries of user input in the form of an of an array of arrays. These entries are two values separated by a space i.e. user inputs 1 followed by a space followed by a 4 providing the array ["1","4"]

#user prompt repeated 7 times    
puts "enter segments: "
e1 = gets.chomp.split
#etc...

entries = [e1, e2, e3, e4, e5, e6, e7] #e.g. 'eX' may be of form ["n", "n2"]
new_values = []


@dict = [2,3,1,2,3,2,3,3,1]
entries.each do |convert|
    convert.each do |get_integers|
        get_integers.each do |get_strings|
            new_values << @dict[get_strings.to_i]
        end
    end
end

array_of_new = new_values.slice(2)

I am trying to:

Convert the elements from each subarray in entries to integers
Then in the entries subarrays I want to replace each element i with @dict[i]

The code I have does all of the above but I end up with a flattened array with all the new values.

How do I break the final array back up into a new array of arrays (so with the same structure as the entries array)? I tried using the slice method, but this is just giving me back the element in the position I am slicing.

Also, I am positive there is a better way to accomplish what I am doing, so if anyone has any advice, I am open to it!

Does something like new_values.map { |x| Array(x) } do what you want? — Andrew
– Andrew, Commented Jan 25, 2016 at 22:57

Sagar Pandya · Accepted Answer · 2016-01-26 04:01:17Z

1

Try something like this:

entries = []
7.times do 
    puts "enter segments: "
    entries << gets.chomp.split.map!{|e| e.to_i }
end

@dict = [2,3,1,2,3,2,3,3,1]
array_of_new = []

entries.each do |sub_array|
    s_arr = []
    sub_array.each do |element| 
        s_arr << @dict[element]
    end
    array_of_new << s_arr
end

p array_of_new

If you wanted to use the each_slice method then you could do something like this:

entries = []
7.times do 
    puts "enter segments: "
    entries << gets.chomp.split.map!{|e| e.to_i }
end


@dict = [2,3,1,2,3,2,3,3,1]
arr = []

entries.each do |sub_array|
    sub_array.each do |element| 
        arr << @dict[element]
    end
end

array_of_new = []
arr.each_slice(2) {|s| array_of_new << s }                          

p array_of_new

Update: An even shorter and smarter way would be to actually transform the entries array instead of having to create new container arrays:

entries = []
7.times do 
    puts "enter segments: "
    entries << gets.chomp.split.map!{|e| e.to_i }
end

@dict = [2,3,1,2,3,2,3,3,1]

entries.each do |sub_array|
    sub_array.map!{|e| @dict[e] }
end

p entries

edited Jan 26, 2016 at 4:01

answered Jan 25, 2016 at 23:49

Sagar Pandya

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2 Comments

Jbur43 Over a year ago

This is exceptional. Thank you!

Sagar Pandya Over a year ago

@Jbur43 Glad I could help. Just added a third way which you may find useful too.

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