Importing CSV data into a ruby array/variable
Solution 1
If you try to use FasterCSV in Ruby 1.9 you get a warning saying that the standard Ruby 1.9 CSV library is actually faster. So I used the standard Ruby CSV library. This should work in Ruby 1.9 or 1.8.7.
require 'csv'
module MyConfig
@mac_address_hash = {}
CSV.foreach("config.csv") do |row|
name, mac_address = row
next if name == "Name"
@mac_address_hash[name] = mac_address
end
puts "Now we have this hash: " + @mac_address_hash.inspect
def self.mac_address(computer_name)
@mac_address_hash[computer_name]
end
end
puts "MAC address of Desktop: " + MyConfig.mac_address("Desktop")
The output of this code is:
Now we have this hash: {"Computer"=>" 02-46-81-02-46-cd", "Desktop"=>" 01-23-45-67-89-ab"}
MAC address of Desktop: 01-23-45-67-89-ab
Now what I want you to do is read every line of this code carefully and try to understand what it does and why it is necessary. This will make you a better programmer in the long run.
You could improve this code to lazily load the CSV file the first time it is required.
Solution 2
I'll demonstrate the dirt-simple method. Stuffing everything in a hash as David Grayson did is far more efficient in the long run, but for a run-a-few-times script this might be sufficient.
require 'csv'
config = CSV.read('config.csv')
config.shift # Get rid of the header
# We're done! Start using like so:
p config.assoc("Computer").last #=>" 02-46-81-02-46-cd"
If the leading space is unwanted:
config = CSV.read('config.csv', {:col_sep => ', '})
IMcD23
Updated on December 12, 2020Comments
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IMcD23 over 3 years
I am trying to use a CSV as a settings file in a plugin for the SiriProxy project to use wake-on-lan. This project is based on ruby.
So the csv is as follows:
Name, MACAddress Desktop, 01-23-45-67-89-ab Computer, 02-46-81-02-46-cd
and so on...
So what I would like to happen is that when the variable userAction is "Desktop" for instance, then I query the CSV and it returns the MAC address into another variable. I am lost on how to do this. I have seen the csv and faster_csv but do not know how to get those to work like this.
Thanks in advance!
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IMcD23 over 12 yearsThanks a bunch! I was almost there. You are the best
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dancow over 5 yearsThis solution is way too complicated; @steenslag's is much more idiomatic. I've included a comment to show how the result of CSV.read() can be converted to a Hash.
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dancow over 5 yearsThis should be the answer, with one addition -- the use of
Hash[arr]
will convert the result ofCSV.read()
-- i.e. an array of arrays -- to a Hash:Hash[CSV.read('config.csv', col_sep: ', ')]