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Groups > comp.lang.javascript > #23528
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| From | Joao Rodrigues <groups_jr-1@yahoo.com.br> |
| Newsgroups | comp.lang.javascript |
| Subject | Re: arr.push(obj); |
| Date | Tue, 11 Mar 2014 13:32:34 -0300 |
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On 11/03/2014 12:02, Christoph Michael Becker wrote:
> Joao Rodrigues wrote:
>
>> On 11/03/2014 01:19, jonas.thornvall@gmail.com wrote:
>>
>>> I was wrong it is allowed or at least working.
>>>
>>> <script type="text/javascript">
>>> var arr=[];
>>> for (i=10;i>=-20;i--) {arr[i]=i;}
>>> arr[-22]=-22;
>>> for (i=10;i>=-22;i--) {document.write(arr[i],",");}
>>> </script>
>>
>> According to the section 15.4 of the ECMAScript 5.1 Specification, "A
>> property name P (in the form of a String value) is an array index if and
>> only if ToString(ToUint32(P)) is equal to P and ToUint32(P) is not equal
>> to 232−1". So, I think this is why you can set negative indices to an
>> array. But the array's length property value is always a nonnegative
>> integer less than 232.
>
> If P has a negative value, ToString(ToUint32(P)) can't be equal to P.
> So there can _not_ be negative array indexes.
>
> BTW: 232 should be written as 2^32 or 2³² in this case. :)
Oh, dear! I should have checked the abstract operation ToUint32 first.
<http://www.ecma-international.org/ecma-262/5.1/#sec-9.6>
Thanks!
--
Joao Rodrigues (J.R.)
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arr.push(obj); jonas.thornvall@gmail.com - 2014-03-10 17:38 -0700
Re: arr.push(obj); jonas.thornvall@gmail.com - 2014-03-10 20:19 -0700
Re: arr.push(obj); jonas.thornvall@gmail.com - 2014-03-10 20:28 -0700
Re: arr.push(obj); jonas.thornvall@gmail.com - 2014-03-10 21:19 -0700
Re: arr.push(obj); Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2014-03-11 06:59 -0300
Re: arr.push(obj); Christoph Michael Becker <cmbecker69@arcor.de> - 2014-03-11 16:02 +0100
Re: arr.push(obj); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-03-11 16:22 +0000
Re: arr.push(obj); Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2014-03-11 13:32 -0300
Re: arr.push(obj); "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-03-11 10:21 +0100
Re: arr.push(obj); jonas.thornvall@gmail.com - 2014-03-11 03:53 -0700
Re: arr.push(obj); "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-03-11 14:03 +0100
Re: arr.push(obj); jonas.thornvall@gmail.com - 2014-03-11 07:45 -0700
Re: arr.push(obj); "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-03-11 16:24 +0100
Re: arr.push(obj); jonas.thornvall@gmail.com - 2014-03-11 10:40 -0700
Re: arr.push(obj); jonas.thornvall@gmail.com - 2014-03-11 10:51 -0700
Re: arr.push(obj); Christoph Michael Becker <cmbecker69@arcor.de> - 2014-03-11 19:23 +0100
Re: arr.push(obj); jonas.thornvall@gmail.com - 2014-03-11 15:33 -0700
Re: arr.push(obj); "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-03-12 00:37 +0100
Re: arr.push(obj); jonas.thornvall@gmail.com - 2014-03-11 16:46 -0700
Re: arr.push(obj); "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-03-12 01:05 +0100
Re: arr.push(obj); Christoph Michael Becker <cmbecker69@arcor.de> - 2014-03-12 01:40 +0100
Re: arr.push(obj); Christoph Michael Becker <cmbecker69@arcor.de> - 2014-03-12 00:48 +0100
Re: arr.push(obj); jonas.thornvall@gmail.com - 2014-03-11 15:43 -0700
Re: arr.push(obj); jonas.thornvall@gmail.com - 2014-03-11 16:18 -0700
Re: arr.push(obj); "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-03-12 00:39 +0100
Re: arr.push(obj); Christoph Michael Becker <cmbecker69@arcor.de> - 2014-03-12 00:52 +0100
Re: arr.push(obj); Christoph Michael Becker <cmbecker69@arcor.de> - 2014-03-12 00:49 +0100
Re: arr.push(obj); jonas.thornvall@gmail.com - 2014-03-11 17:16 -0700
Re: arr.push(obj); Christoph Michael Becker <cmbecker69@arcor.de> - 2014-03-12 02:07 +0100
Re: arr.push(obj); jonas.thornvall@gmail.com - 2014-03-11 18:13 -0700
Re: arr.push(obj); Christoph Michael Becker <cmbecker69@arcor.de> - 2014-03-13 02:25 +0100
Re: arr.push(obj); Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-03-13 11:03 +0100
Re: arr.push(obj); jonas.thornvall@gmail.com - 2014-03-12 07:46 -0700
Re: arr.push(obj); Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-03-12 01:27 +0100
Re: arr.push(obj); Christoph Michael Becker <cmbecker69@arcor.de> - 2014-03-12 01:44 +0100
Re: arr.push(obj); Christoph Michael Becker <cmbecker69@arcor.de> - 2014-03-11 16:26 +0100
Re: arr.push(obj); Carlos Pedro <carlospedr@gmail.com> - 2014-03-11 09:21 -0700
Re: arr.push(obj); Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-03-11 18:01 +0100
Re: arr.push(obj); Christoph Michael Becker <cmbecker69@arcor.de> - 2014-03-11 19:15 +0100
Re: arr.push(obj); Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-03-11 20:32 +0100
Re: arr.push(obj); Christoph Michael Becker <cmbecker69@arcor.de> - 2014-03-12 01:01 +0100
Re: arr.push(obj); Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-03-12 04:08 +0100
Re: arr.push(obj); Christoph Michael Becker <cmbecker69@arcor.de> - 2014-03-12 18:00 +0100
Re: arr.push(obj); Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2014-03-11 06:24 -0300
Re: arr.push(obj); jonas.thornvall@gmail.com - 2014-03-11 03:47 -0700
Re: arr.push(obj); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-03-11 15:19 +0000
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