array_floe
This small extension to ruby's Array class simplifies the reasonably-common need to specially handle "floe"--i.e., first, last, odd, even--when iterating through the elements of an array. It's particularly handy for generating CSS classes.
Full Rdoc is available at http://rubydoc.info/gems/array_floe
Usage
The gem provides two additional iterators, Array#each_with_floe and Array#each_with_index_floe, that provide a "floe" object for each element in the array:
ary.each_with_floe do |element, floe|
if floe.first?
puts "#{element} is the first element"
end
if floe.last?
puts "#{element} is the last element"
end
if floe.odd?
puts "#{element} is an odd-numbered element"
end
if floe.even?
puts "#{element} is an even-numbered element"
end
end
ary.each_with_index_floe do |element, i, floe|
assert_equal(i == 0, floe.first?)
assert_equal(i == ary.size-1, floe.last?)
assert_equal(i % 2 == 1, float.odd?)
assert_equal(i % 2 == 0, float.even?)
end
If no block is given, an enumerator is returned instead.
The "floe" object's to_s method returns a space-separated list of "first",
"last", "odd", and "even" as appropriate:
[:a, :b, :c, :d].each_with_floe.collect{|element, floe| floe.to_s} #=> [ "first even", "odd", "even", "last odd" ]
floe.to_s is particularly useful to construct CSS classes when generating
HTML. For example, this haml snippet:
%table
- [:a, :b, :c, :d].each_with_floe do |row, floe|
%tr{:class => floe}
%td= row
would yield this HTML snippet:
<table>
<tr class="first even">
<td>a</td>
</tr>
<tr class="odd">
<td>b</td>
</tr>
<tr class="even">
<td>c</td>
</tr>
<tr class="last odd">
<td>d</td>
</tr>
</table>
Installing
Standard installation from http://rubygems.org/gems/array_floe
% gem install array_floe
or, if you're using bundler, include this line in your Gemfile:
gem "array_floe"
Ruby Versions
Tested on ruby 1.8.7 and 1.9.3 and 2.0.0
Copyright
Released under the MIT License. See LICENSE.txt for further details.