Hey. How can I get a total number of rows in a file (do not want to do it with loop). I'm reading CSV file.
Example 1
CSV.open('clients.csv', 'r')
Example 2
FasterCSV.foreach('clients.csv')
Thx.
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How large is your file?
This option loads the entire file into memory, so if there are size/memory concerns it might not work.
numrows = FasterCSV.read('clients.csv').size
This option uses Ruby's built-in CSV module, which as you know is quite slow, but it does work. It also loads the entire file into memory:
numrows = CSV.readlines('clients.csv').size
Both FasterCSV.read and CSV.readlines return arrays of arrays, so you can use any array magic you want on the results.
Roadmaster
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Ruby 1.9 don't support FasterCSV – VP. Mar 26 '10 at 23:55
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Then I suppose the other solution might be more useful in Ruby 1.9 - it's slow but it works :) Thanks for the heads-up. – Roadmaster Mar 27 '10 at 00:07
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1@VP I think that's not quite right. Actually FasterCSV _is_ the csv in 1.9: http://stackoverflow.com/a/6090840/603309 – Kjellski Aug 06 '12 at 07:47
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@Roadmaster what if there is a large cvs file (e.g 1GB) and we don't want to load it into memory? – Meer Jul 11 '15 at 18:31