coding, ruby

Map Reduce plus filter using Ruby

Previous two articles were dedicated to JavaScript and map reduce and filtering of somewhat large data, elegance of code, etc.

Going forward, i’d like to evaluate other languages doing the same exact thing.

And i’m curious about performance too.

 

Here is my version of the same code i wrote but in Ruby (Ruby 2.1.1 was used). Didn’t even run in Jruby 1.7 unfortunately.

 

 class Time
 	def to_ms
 		(self.to_f * 1000.0).to_i
 	end
 end

 total = 300 *10000
 data = Array.new

 total.times.each {|x|
 	data.push({name: 'it', salary: 33*x})
 }

 data.push({name: "it", salary: 100})
 data.push({name: "acc", salary: 100})

 def self.timeMe
 	start = Time.now.to_ms
 	yield
 	endtime = Time.now.to_ms
 	puts "Time elapsed #{endtime - start} ms"
 end

 timeMe do
 	boom = data.map {|j|  j[:salary] if j[:name] =='it' }.compact.reduce(:+)
 	puts "and  boom: #{boom} "
 end

Result

 

and  boom: 148499950500100
Time elapsed 1194 ms

Not bad but not as fast as javascript, probably due to array containing Hash, as opposed to one of the core types in javascript (a simple object) .

I’m not entirely sure why Jruby didn’t run, id love to learn.

Update (2014/april 18): Java 1.6 with JVM parameters (needed) posted results of around 600ms , JVM 1.8 didn’t seem to work at the moment.

On another note, Ruby’s syntax is simply lovely

 

data.map {|j|  j[:salary] if j[:name] =='it' }.compact.reduce(:+)

 

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