From: Mmcolli00 Mom <mmc_collins@...>
Date: 2009-01-15T13:51:06+09:00
Subject: undefined method `[]' for nil:NilClass - how to prevent?

This returns correct value so long as I do not use array[0][i]. The
error is:

>searchArray.rb:13: undefined method `[]' for nil:NilClass (NoMethodError)
>  from shifting1.rb:7:in `each_line'
>  from shifting1.rb:7
>Exit code: 1
>
#**************************************
#Searches through a text file and, at one row at a time, counts how many
occurrences of the value exist for the column. For instance, if word,
'bird' exists in column1 row1 then count how many birds exist for the
whole column. Next..count the occurrences of bird in the column 2. If
the numbers do not match then outputs "Value does not contain a match:"
+Value.

I am having this issue with NilClass a lot this week. What do you think
I should change?

##start code

 col1 = 0
 col2 = 0

 File.open('temp.txt', 'r+').each_line do |temp|
   array = []
   i = 0
  array = temp.chomp.split(",",0)

   arrayVal1 = array[0][i]
   arrayVal2 = array[1][i]

     if array[0] == arrayVal1 then
       col1 = col1 + 1
      end

     if array[1] == arrayVal2 then
       col2 = col2 + 1
    end
     i = i + 1

  if col1 != col2 then
    puts "Value does not contain a match:"
    puts arrayVal1
 end

end

##end code

Attachments:
http://www.ruby-forum.com/attachment/3164/searchArray.rb

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