Convert an array in ruby into an output stream - ruby

Question

I have an array [2, 4, 6, 8, 3], i need to convert it into an output stream as below:
2 4 6 8 3
Converting into string and chopping the commas and quotes is not helping as it always prints as "2 4 6 8 3" if it is a string.
This is the input given:
5
2 4 6 8 3
This is the code i wrote
def insertionSort( ar)
key = ar.last
(ar.size-2).downto(0){
|x|
if(key < ar[x])
ar[x+1] = ar[x]
p ar
else
ar[x+1] = key
p ar
break
end
}
end
# Tail starts here
count = gets.to_i
ar = gets.strip.split.map {|i| i.to_i}
insertionSort( ar )
My Output:
[2, 4, 6, 8, 8]
[2, 4, 6, 6, 8]
[2, 4, 4, 6, 8]
[2, 3, 4, 6, 8]
Expected Outuput:
2 4 6 8 8
2 4 6 6 8
2 4 4 6 8
2 3 4 6 8
Test Result:
Fail

Answer 1

Your question isn't at all clear, but, maybe this is what you want:
ary = [2, 4, 6, 8, 3]
ary.join(' ') # => "2 4 6 8 3"
ary * ' ' # => "2 4 6 8 3"
Perhaps you don't understand how to loop?
ary = [2, 4, 6, 8, 3]
5.times do
puts ary.join(' ')
end
# >> 2 4 6 8 3
# >> 2 4 6 8 3
# >> 2 4 6 8 3
# >> 2 4 6 8 3
# >> 2 4 6 8 3
Or maybe you don't understand how command-line apps read STDIN?
Dealing with STDIN is useful when writing pipes: Chaining one small specialized application to another, and letting them collectively do a big task is the basic premise for *nix systems. Monolithic apps that try to do everything are a major PITA to write/maintain and use.
If you want to read a single line of input, either from STDIN or the keyboard, gets is good. If you want to read a series of lines, look at Ruby's ARGF class, and become very familiar with how STDIN and $stdin work.
Writing a Ruby command-line script is easy, but, just like doing it in Perl, Python or C, you have to be aware how the incoming data is accessed, what type of data it is (always a string), and how it's structured: characters terminated by a new-line ("\n") or carriage-return+new-line ("\r\n").
Perhaps you don't understand how to_i works?
"2 4 6 8 3".to_i # => 2
"24683".to_i # => 24683
"2_4_6_8_3".to_i # => 24683
to_i reads the string from the first character and continues until it finds a non-digit. So, in the above examples, 2 is the first digit in the first string, followed by a space. The space is a non-digit so to_i stops processing and only returns 2. In the second example, there are no spaces, so to_i processes the entire string and returns it as a single value. In the third, because Ruby, like some other languages, accepts _ as a part of a numeric string, to_i returns the full value again. _ is used to mark the comma positions in values, like 1_000_000.
As you write more code, take the time to write it clearly and cleanly. You want code that reduces the visual noise and makes it easy to take into your brain. Ruby makes it easy to write clean and expressive code that is easy to understand, but bad coding style can reduce Ruby code to unreadable quickly, especially to those of us who are used to seeing it written in an idiomatic style.
This isn't an attempt to fix your algorithm, it's just to show how you should style your code:
def insertion_sort(ar)
key = ar.last
(ar.size - 2).downto(0) { |x|
if (key < ar[x])
ar[x + 1] = ar[x]
p ar
else
ar[x + 1] = key
p ar
break
end
}
end
# Tail starts here
count = gets.to_i
ar = gets.strip.split.map { |i| i.to_i }
insertion_sort(ar)
Methods are always written in snake_case, never CamelCase.
Use whitespace; It gives your eyes and brain logical breaks that help define what is going on. Operators and control structures benefit from having whitespace before and after, and above and below.
Use spaces to indent, with tab-stops set to 2-spaces. This is the Ruby standard. Why those? Consistency as people move code between different editors; If you're working in a professional coding house you'll probably find a lot more rigid coding standards in place.

Answer 2

> a = [1, 2, 3, 4]
> puts "[#{a.join(', ')}]"
=> [1, 2, 3, 4]
Does not work on multi-dimensional arrays, or arrays within arrays.
> a = [1, 2, [3, 4, 5, 6], [7, 8, 9]]
> puts "[#{a.join(', ')}]"
=> [1, 2, 3, 4, 5, 6, 7, 8, 9]
But, if you do this, it should work for multi-dimensional arrays:
Example 1:
> a = [1, 2, [3, 4, 5, 6], [7, 8, 9]]
> a.each do |sub_a|
> puts "[#{a.join(', ')}]"
> end
=> [1, 2, [3, 4, 5, 6], [7, 8, 9]]
Example 2:
> a = [1, [2, [3, 4, [5, 6, 7, 8], 9, 0]], 'x', 'y', 'z']
> a.each do |sub_a|
> puts "[#{a.join(', ')}]"
> end
=> [1, [2, [3, 4, [5, 6, 7, 8], 9, 0]], "x", "y", "z"]

Answer 3

After reading the HackerRank "Insertion Point" question you referenced, the input appears to be coming from stdin. If your code includes
s = gets
it will wait for you to enter a string. Suppose you enter 1 2 3 4 (no quotes). Then s will hold "1 2 3 4\n".
If you want to convert this to an array:
a = s.split # => ["1","2","3","4"]
If you want the elements of a to be integers, rather than strings:
a.map! {|e| e.to_i} # => [1,2,3,4]
which (since Ruby version 1.9) can also be written:
a.map!(&:to_i) # => [1,2,3,4]
The 'Ruby way' would be to chain these operations:
a = gets.split.map(&:to_i) # => [1,2,3,4]
Note that we don't need ! with map now.
If you want this array to be a row i of some (existing array) b
b[i] = a