title: Array TypeError: can't convert Fixnum into String
body: <p>I am experimenting with arrays, and am reading the book "Beginning Ruby on Rails" by Steve Holzner. I made the program:</p>
  
  <pre><code>array = ['Hello', 'there', 1, 2]
  puts array[1]
  puts array[3]
  puts array.length
  array2 = Array.new
  puts array2.length
  array2[0] = "Banana"
  array2[1] = 6
  puts array2[0] + " " + array2[1]
  puts array3.length
  </code></pre>
  
  <p>It doesn't do much, but when i run it i get the error</p>
  
  <pre><code>arrays.rb:9:in `+': can't convert Fixnum into String (TypeError)
      from arrays.rb:9
  </code></pre>
  
  <p>Why do I get this error?</p>