Finding the index of an item using a block
Posted Friday, April 18, 2008Update: Ruby 1.8.7 also has this.
Ruby 1.9 has it but if you’re not that bleeding edge, you can have it now:
class Arraydef index_with_block(*args)
return index_without_block(*args) unless block_given?
each_with_index do |entry, index|
return index if yield(entry)
end
nil
end
alias_method :index_without_block, :index
alias_method :index, :index_with_block
def rindex_with_block(*args)
return rindex_without_block(*args) unless block_given?
index = sizereverse_each do |entry|
index -= 1
return index if yield(entry)
end
nil
end
alias_method :rindex_without_block, :rindex
alias_method :rindex, :rindex_with_blockend
If you’re using Rails you can substitute the two calls each to alias_method with a single call to alias_method_chain.
About Simon
Husband, Father, One-time Entrepreneur.
Aka Haruki Zaemon. Aka Sampy.
In my younger years I wanted to save the world; now I'm happy solving bigger problems than I create.
If I didn't need to work I'd be teaching Aikido and spending all my free time with my amazing wife and two children in Woodend, Victoria, Australia.
Books
Beginning Algorithms
with James Ross
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