From: Karl Allmark <karl.allmark@...>
Date: 2006-01-12T22:06:56+09:00
Subject: Re: Newbie question about multiple assignments

>> Alex wrote:
>>> irb(main):091:0> a=1
>>> => 1
>>> irb(main):092:0> b=2
>>> => 2
>>> irb(main):093:0> a,b=b,a
>>> => [2, 1]
>>> irb(main):094:0> a=1
>>> => 1
>>> irb(main):095:0> b=2
>>> => 2
>>> irb(main):096:0> a, b = b, a = a, b
>>> => [2, 1, 2]                           <-- Why?
>>>  What is the order for the assignments
>>>
>>
>> Keep in mind, that
>>
>> a, b = c, d
>>
>> is just shorthand for
>>
>> a, b = [c, d]
>>
>> So, your expression
>>
>> a, b = b, a = a, b
>>
>> gets parsed as
>>
>> a, b = [b, a = a, b]
>>
>> and thus produces the observed behaviour.
>>
>> HTH,
>>
>> Michael
>>
>>
>
>
>That doesn't seem to explain the return value [2, 1, 2] of the expression.
>
>David Vallner

Hi List

Just getting up to speed with ruby myself, try reading Davids explaination
as:

a, b = [b,(a = a), b]

Karl Allmark