From: Love U Ruby <lists@...>
Date: 2013-02-17T05:06:01+09:00
Subject: How the string concatenation operator hackes(modifies) the string contents of frozen array?

Hi,

Find the below code:

>> b = %w[foo bar gis]
=> ["foo", "bar", "gis"]
>> b.frozen?
=> false
>> b.object_id
=> 7298560
>> b.freeze
=> ["foo", "bar", "gis"]
>> b.object_id
=> 7298560
>> b[0] <<  "lish"
=> "foolish"
>> b.object_id
=> 7298560

#How the "<<" operator made the change to the string where as being a
concatenation operator "+" on string couldn't do that,rather prevented
by the array?

>> b[0]=b[0] + "lish"
RuntimeError: can't modify frozen Array
  from (irb):16:in `[]='
  from (irb):16
  from /usr/bin/irb:12:in `<main>'

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