DZone Snippets: rails code

Matrix rotator

aptiva (FjÃ¶lnir Ã?sgeirsson) — Fri, 02 Feb 2007 01:07:05 GMT

This method rotates a matrix
Example output:
~/Desktop% ruby rotate.rb
normal
12345
00000
fooba
rotated left
50a
40b
30o
20o
10f
rotated right
f01
o02
o03
b04
a05



def rotateMatrix(matrix, direction)

  # - You must Rotate the matrix neo!

  oldMap = matrix



  # Get the number of lines in the old map (they're the new columns)

  lineCount = oldMap.size

  # Get the number of columns in the old map (We have that many rows now)

  columnCount = oldMap[0].size

  @map = []

  columnCount.times { @map.push [] }



  # Loop through every line in the old map, retrieve the appropriate column

  # and make a horizontal column with it's contents

  # we'll take one (old)line at a time and rotate it.

  onLine = 0

  oldMap.each do |oldLine|

    onColumn = 0

    oldLine.each do

      case direction

      when :right

        @map[(columnCount - 1) - onColumn][(lineCount - 1) - onLine] = oldLine[(columnCount - 1) - onColumn]

      when :left

        @map[onColumn][onLine] = oldLine[(columnCount - 1) - onColumn]

      end

      onColumn += 1

    end

    onLine += 1

  end

  @map

end



def rotateRight(matrix)

  rotateMatrix(matrix, :right)

end



def rotateLeft(matrix)

  rotateMatrix(matrix, :left)

end

File icon giver/getter/whatever

aptiva (FjÃ¶lnir Ã?sgeirsson) — Thu, 07 Sep 2006 19:32:28 GMT

This code uses acts_as_attachment (that's the attachment.filename) but you can of course replace it with anything.
It gets the file extension then looks up that extension in a dir full of files named extension.png
if none is found, unknown.png is used



<%

extension = File.extname(attachment.filename).gsub(/\./, "")

# get a file icon

icon_path = nil

Dir.entries("#{RAILS_ROOT}/public/images/filetypes").each do |entry|

	entry_extension = File.extname(entry)

	if entry.gsub(entry_extension, "") === extension

		icon_path = "/images/filetypes/" + entry

		break

	end

end

icon_path = "/images/filetypes/unknown.png" if icon_path.nil?

 %>

<%= image_tag icon_path %>

<%= attachment.filename %>

all_children!

aptiva (FjÃ¶lnir Ã?sgeirsson) — Sun, 03 Sep 2006 16:11:27 GMT

This snippet just gives you all the children of a model that acts_as_tree



  def all_children

    Page.all_children_for self

  end

  

  def self.all_children_for(parent, arr = [])

    parent.children.each { |child| arr.push child }

    parent.children.each { |child| all_children_for child, arr }

    arr

  end