RoR show elements in two columns

Question

how can i split elements of a model into two equally sized pieces so that i can show them in two columns?

i have this:

element 1
element 2
element 3
element 4
element 5


and i want this:

element 1    element 4
element 2    element 5
element 3

split() unfortunately removes the middle element.

Answer 1

Array#in_groups_of is an core extension and only available in Rails. What it uses though is the each_slice method.

You could use it like this:

a = ["element 1", "element 2", "element 3", "element 4", "element 5"]
a.each_slice((a.size/2.0).ceil) { |slice| puts slice } if a.size > 0

will give you

["element 1", "element 2", "element 3"]
["element 4", "element 5"]

Note that you must check that a.size is bigger then 0 or you will get an ArgumentError exception due to invalid slice size.

Answer 2

as i only need to use this in rails, this worked for me:

>> a = [1,2,3,4,5]
=> [1, 2, 3, 4, 5]
>> a.in_groups_of( (a.size/2.0).ceil, false ) if a.size > 0
=> [[1, 2, 3], [4, 5]]

Answer 3

Check out Array#in_groups_of

This will slice an array in chunks of your liking.

Answer 4

One approach is to use jQuery. There are several plugins that can accomplish this for you.

Subsequently, after you have the two chunks, start filling up a div with the first group, once you get to the end, start the second group in a second div. Then use css to position and style the two divs beside one another.

Answer 5

Where are you trying to show these elements?

If it's in a view, you should not be modifying your model; your models should stay independent from your presentation.

If you want to present results on a web page, you must use html and css in your view. Even in your view, you probably won't need to "split" your elements into sub arrays.

See this page , for example. If you look at the source code, the lists are allways "one after the other", without splitting into groups. The CSS conditions how the text is positioned.