From: Jim Freeze <jim@...>
Date: 2001-07-13T04:56:37+09:00
Subject: [ruby-talk:17747] What is Array#- ?

While following the Array thread, I noticed the minus
operator. So I tried:

irb(main):001:0> a=%w{1 2 3}
["1", "2", "3"]
irb(main):002:0> a-["3"]
["1", "2"]

All well and good.
But then I tried:

irb(main):003:0> a=%w{1 1 2 2 3 3 3}
["1", "1", "2", "2", "3", "3", "3"]
irb(main):004:0> a-["3"]
["1", "2"]

This looks like this is really the minus operation
mixed with the uniq operation.

a1 - a2 => a1.uniq - a2.uniq
or maybe
a1 - a2 => (a1-a2).uniq

Someone care to explain this behavior?

Thanks

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Jim Freeze
jim@freeze.org
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