Question

I have my CSV file imported as such:

records = FasterCSV.read(path, :headers => true, :header_converters => :symbol) 

How can I get the unique occurrences of my data? For instance, here some sample data:

ID,Timestamp test,2008.12.03.20.26.32 test,2008.12.03.20.26.38 test,2008.12.03.20.26.41 test,2008.12.03.20.26.42 test,2008.12.03.20.26.43 test,2008.12.03.20.26.44 cnn,2008.12.03.20.30.37 cnn,2008.12.03.20.30.49 

If I simply call records[:id], I just get:

testtesttesttesttesttestcnncnn 

I would like to get this:

testcnn 

How can I do this?

Answer 1

If your data is not masive you can use the Set class.

Here’s an example:

p ['cnn','test','test','test','test','cnn','cnn'].to_set.to_a => ['cnn', 'test'] 

Here’s a simple benchmark:

require 'set' require 'benchmark'  Benchmark.bm(5) do |x|   x.report('Set')   do     a = []     20_000.times do |i|       a << 'cnn'<< 'test'     end     a.to_set.to_a   end end  =>            user     system      total        real  Set    0.110000   0.000000   0.110000 (  0.109000)