Module: Enumerable

Defined in:
lib/enumerable_extensions.rb

Overview

Enumerable Extensions

Author

Joel Parker Henderson, [email protected]

Copyright

Copyright © 2006-2008 Joel Parker Henderson

License

CreativeCommons License, Non-commercial Share Alike

License

LGPL, GNU Lesser General Public License

Ruby Enumerable base class extensions.

Instance Method Summary collapse

Instance Method Details

#cat(prefix = nil, suffix = nil) ⇒ Object

Concatenate the items into a string.

Example

arr=['anne','beth','cate']
arr.cat => "annebethcate"

You can optionally provide a prefix and suffix.

Example

arr.cat("+") => "+anne+beth+cate"
arr.cat("+","-") => "+anne-+beth-+cate-"

You can easily wrap items in HTML tags.

Example

arr=['anne','beth','cate']
arr.cat("<li>","</li>\n")
=>
<li>anne</li>
<li>beth</li>
<li>cate</li>



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# File 'lib/enumerable_extensions.rb', line 140

def cat(prefix=nil,suffix=nil)
 if prefix
  if suffix
   inject(""){|sum,s| sum += prefix + s.to_s + suffix}
  else
   inject(""){|sum,s| sum += prefix + s.to_s }
  end
 else
  inject(""){|sum,s| sum += s.to_s }
 end
end

#map_id ⇒ Object

map item => item.id



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# File 'lib/enumerable_extensions.rb', line 22

def map_id
  map{|x| x.id}
end

#map_to_sym ⇒ Object

map item => item.to_sym



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# File 'lib/enumerable_extensions.rb', line 28

def map_to_sym
  map{|x| x.to_sym}
end

#nitems_until ⇒ Object

enum.nitems_until {| obj | block } => number of items Returns the number of leading elements for which block is false.



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# File 'lib/enumerable_extensions.rb', line 94

def nitems_until
  n = 0
  each{|x|
    if yield(x) 
      break
    else
      n+=1
    end
  }
  return n
  irb
end

#nitems_while ⇒ Object

enum.nitems_while {| obj | block } => number of items Returns the number of leading elements for which block is not false or nil.



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# File 'lib/enumerable_extensions.rb', line 85

def nitems_while
  n = 0
  each{|x| yield(x) ? (n+=1) : break}
  return n
end

#nitems_with_index ⇒ Object

enum.nitems_with_index {|obj,i| block } => number of items Calls block with two arguments, the item and its index, for each item in enum. Returns the number of leading elements for which block is true.



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# File 'lib/enumerable_extensions.rb', line 111

def nitems_with_index
  i = 0
  each{|x| yield(x,i) ? (i+=1) : break}
  return i
end

#select_until ⇒ Object

enum.select_until {|obj| block } => array Returns an array containing the leading elements for which block is false or nil.



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# File 'lib/enumerable_extensions.rb', line 51

def select_until
  a = []
  each{|x| yield(x) ? break : (a << x)}
  return a
end

#select_while ⇒ Object

enum.select_while {|obj| block } => array Returns an array containing the leading elements for which block is not false or nil.



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# File 'lib/enumerable_extensions.rb', line 42

def select_while
  a = []
  each{|x| yield(x) ? (a << x) : break}
  return a
end

#select_with_index ⇒ Object

enum.select_with_index {|obj,i| block } => array Calls block with two arguments, the item and its index, for each item in enum. Returns an array containing the leading elements for which block is not false or nil.



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# File 'lib/enumerable_extensions.rb', line 61

def select_with_index
  i = 0
  a = []
  each{|x| 
    if yield(x,i)
      a << x
      i+=1
    else
      break
    end
  }
  return a
end