From: Michael Ulm <michael.ulm@...>
Date: 2006-01-12T21:39:00+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


-- 
Michael Ulm
R&D Team
ISIS Information Systems Austria
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