Undefined method for array

Question

So I'm receiving the error message "undefined method 'ip_histogram' for # (NoMethodError)" with the following code

class CommonLog
  def initialize(logfile)
    @logfile = logfile
  end
  def readfile
    @readfile = File.readlines(@logfile).map { |line|
      line.split()
    }
    @readfile = @readfile.to_s.split(" ")
  end
  def ip_histogram
    @ip_count = 0
    @readfile.each_index { |index|
      if (@readfile[index] =~ /\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}/ )
        puts @readfile[index]
        puts @ip_count += 1
      end
    }
  end
end

my_file = CommonLog.new("test_log")
cleaned_file = my_file.readfile
puts cleaned_file.ip_histogram

I'm trying to read the array in and check it with regex. It works if I take the code out of the method and just throw it into the main program, but I'd like to know why it doesn't work as a method.

Anthony · Accepted Answer · 2015-04-27 23:52:14Z

3

You're assigning the results of CommonLog#readfile to a new variable cleaned_file. You didn't supply any input but I'm going to assume @readfile is an array at this point.

That means your code is going to assume there's an instance method ip_histogram on the Array class when in fact there is not.

You'll simply want to run these in sequence to get the result you're after:

clog = CommonLog.new("test_log")
clog.readfile
clog.ip_histogram

The primary difference here is that we're not using the return value of readfile as it only needs to set the variable in the method for ip_histogram to work.

edited Apr 27, 2015 at 23:52

answered Apr 27, 2015 at 13:10

Anthony

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1 Comment

EnduranceMan Over a year ago

Ah, that fixed it right away! All methods fully functional, thanks so much for your help! You're a lifesaver!

sawa · Accepted Answer · 2015-04-27 13:11:43Z

0

The return value of my_file.readfile is an array. Unless you defined ip_histogram in Array class, you cannot call it on cleaned_file.

To define ip_histogram on Array (with different definition than in your code):

class Array
  def ip_histogram
    ...
  end
end

edited Apr 27, 2015 at 13:11

answered Apr 27, 2015 at 13:07

sawa

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1 Comment

EnduranceMan Over a year ago

How would I define ip_histogram on Array, define it on the Array class? Inherit the Array class into the CommonLog class?

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