From: SpringFlowers AutumnMoon <summercoolness@...>
Date: 2007-10-01T11:56:02+09:00
Subject: Re: got a range from an array, but looking for other ways of doing it

SpringFlowers AutumnMoon wrote:
> Simon Schuster wrote:
>> a is an array. I'm trying to chop the first and last third off. or,
>> choose only the middle third. can be a rough third.

that's strange, if i do

a = Array(1..100)
    ==>[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 1
6, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 3
1, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 4
6, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 6
1, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 7
6, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 9
1, 92, 93, 94, 95, 96, 97, 98, 99, 100]

a[0..a.size/2] = a[a.size*2/3..-1] = nil
    ==>nil
a
    ==>[52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64,
65, 66]


a = Array(1..100)
    ==>[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 1
6, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 3
1, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 4
6, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 6
1, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 7
6, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 9
1, 92, 93, 94, 95, 96, 97, 98, 99, 100]

a[0..a.size/3] = a[a.size*2/3..-1] = nil
    ==>nil
a
    ==>[35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,
48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62,
63, 64, 65, 66]


shouldn't it be  a[0..a.size/2] = a[a.size*2/3..-1] = nil
really?

because it is equiv to

a[0..a.size/2] = (a[a.size*2/3..-1] = nil)
a[0..a.size/2] = (nil)

by the time the Right most got evaluated, the array is roughly 66 
elements, so it should be half the size to be deleted.  looks like the 
interpreter precalculate a.size / 2 before the final assignment.



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