Take a look at [Enumerable#each_slice][1]:

    foo.each_slice(3).to_a
    #=&gt; [[&quot;1&quot;, &quot;2&quot;, &quot;3&quot;], [&quot;4&quot;, &quot;5&quot;, &quot;6&quot;], [&quot;7&quot;, &quot;8&quot;, &quot;9&quot;], [&quot;10&quot;]]


  [1]: http://apidock.com/ruby/Enumerable/each_slice

If you&#39;re using rails you can also use [in_groups_of][1]:

    foo.in_groups_of(3)


  [1]: http://apidock.com/rails/Array/in_groups_of

I&#39;ve read some texts about declarative/functional programming (languages), tried out Haskell as well as written one myself. From what I&#39;ve seen, functional programming has several advantages over the classical imperative style:

- Stateless programs; No side effects
- Concurrency; Plays extremely nice with the rising multi-core technology
- Programs are usually shorter and in some cases easier to read
- Productivity goes up (example: Erlang)

- Imperative programming is a very old paradigm (as far as I know) and possibly not suitable for the 21st century

Why are companies using or programs written in functional languages still so &quot;rare&quot;? 

Why, when looking at the advantages of functional programming, are we still using imperative programming languages?

Maybe it was too early for it in 1990, but today?

Why hasn&#39;t functional programming taken over yet?

I was wondering if there was any key mapping in Vim to allow me to indent certain lines of code (whether those lines have been selected in visual mode, or *n* lines above/below current cursor position).

So basically something that converts the following 

    def my_fun(x, y):
        return x + y

to

    #def my_fun(x, y):
    #    return x + y

I am okay with using either `#` or `&quot;&quot;&quot;` for commenting out the relevant lines. Ideally, I would also like the same keymapping to uncomment the lines if the given lines have been commented out.

How to comment out a block of Python code in Vim

I have an array

    foo = %w(1 2 3 4 5 6 7 8 9 10)

How can I split or &quot;chunk&quot; this into smaller arrays?

    class Array
      def chunk(size)
        # return array of arrays
      end
    end
    
    foo.chunk(3)
    # =&gt; [[1,2,3],[4,5,6],[7,8,9],[10]]

How to split (chunk) a Ruby array into parts of X elements?

I have an array
<pre><code class="hljs language-ini">foo = %w(1 2 3 4 5 6 7 8 9 10)
</code></pre>
How can I split or "chunk" this into smaller arrays?
<pre><code class="hljs language-lua">class Array
 def chunk(size)
 # return array of arrays
 end
end

foo.chunk(3)
# => [[1,2,3],[4,5,6],[7,8,9],[10]]
</code></pre>

In Ruby, what&#39;s the best way to convert a string of the format: `&quot;{ 2009, 4, 15 }&quot;` to a Date?

Ruby: convert string to date

How can I get the first character in a string using Ruby?

Ultimately what I&#39;m doing is taking someone&#39;s last name and just creating an initial out of it.

So if the string was &quot;Smith&quot; I just want &quot;S&quot;.

Ruby: How to get the first character of a string

How do I transform

    www.bestbuy.com/site/Electronics\Audio\abcat0200000.c=3fid=3dabcat0200000

into its original format?

    www.bestbuy.com/site/Electronics/Audio/abcat0200000.c?id=abcat0200000

Is there a `urldecode`?



urldecode in ruby?

I understand that it is a replacement for ActiveRecord and that it uses objects instead of queries. 

But...
 
why is this better? 

will objects/queries be &quot;easier&quot; to create?

will it lead to more efficient SQL queries?

will it be compatible with all major DBs? - I assume it will.

will it be easier/harder to use with stored procedures?

What exactly is Arel in Rails 3.0?

How do we add comments in erb files, if we do not want them to be generated into the html content? 

Best way to add comments in erb

I&#39;m writing a bash script that needs to loop over the arguments passed into the script.  However, the first argument shouldn&#39;t be looped over, and instead needs to be checked before the loop.

If I didn&#39;t have to remove that first element I could just do:

    for item in &quot;$@&quot; ; do
      #process item
    done

I could modify the loop to check if it&#39;s in its first iteration and change the behavior, but that seems way too hackish.  There&#39;s got to be a simple way to extract the first argument out and then loop over the rest, but I wasn&#39;t able to find it.

Remove first element from $@ in bash

In what cases I should use Array(Buffer) and List(Buffer). Only one difference that I know is that arrays are nonvariant and lists are covariant. But what about performance and some other characteristics? 

Difference between Array and List in scala

How can I see in Java if an Object is an array without using reflection?
And how can I iterate through all items without using reflection?

I use Google GWT so I am not allowed to use reflection :(

I would love to implement the following methods without using refelection:

    private boolean isArray(final Object obj) {
      //??..
    }
    
    private String toString(final Object arrayObject) {
      //??..
    }

BTW: neither do I want to use JavaScript such that I can use it in non-GWT environments.

How to see if an object is an array without using reflection?

I was asked this interview question recently:

&gt; You&#39;re given an array that is almost sorted, in that each of the `N` elements may be misplaced by no more than `k` positions from the correct sorted order. Find a space-and-time efficient algorithm to sort the array.

I have an `O(N log k)` solution as follows.

Let&#39;s denote `arr[0..n)` to mean the elements of the array from index `0` (inclusive) to `N` (exclusive).

* Sort `arr[0..2k)`
    * Now we know that `arr[0..k)` are in their final sorted positions...
    * ...but `arr[k..2k)` may still be misplaced by `k`!
* Sort `arr[k..3k)`
    * Now we know that `arr[k..2k)` are in their final sorted positions...
    * ...but `arr[2k..3k)` may still be misplaced by `k`
* Sort `arr[2k..4k)`
* ....
* Until you sort `arr[ik..N)`, then you&#39;re done!
    * This final step may be cheaper than the other steps when you have less than `2k` elements left

In each step, you sort at most `2k` elements in `O(k log k)`, putting at least `k` elements in their final sorted positions at the end of each step. There are `O(N/k)` steps, so the overall complexity is `O(N log k)`.

My questions are:

* Is `O(N log k)` optimal? Can this be improved upon?
* Can you do this without (partially) re-sorting the same elements?

Sorting an almost sorted array (elements misplaced by no more than k)

I&#39;m getting 

&gt; illegal offset type

 error for every iteration of this code. Here&#39;s the code :

    $s = array();
    for($i = 0; $i &lt; 20; $i++){
    	$source = $xml-&gt;entry[$i]-&gt;source;
    	$s[$source] += 1;    
    }
   
    print_r($s)



Content Type	Original Author	Original Content on Stackoverflow
Question	maček	View Question on Stackoverflow
Solution 1 - Ruby	Mladen Jablanović	View Answer on Stackoverflow
Solution 2 - Ruby	Head	View Answer on Stackoverflow

How to split (chunk) a Ruby array into parts of X elements?

Ruby Problem Overview

Ruby Solutions

Solution 1 - Ruby

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How to comment out a block of Python code in Vim

Why hasn't functional programming taken over yet?

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