Retrieving previous array item

[Belmin]

I have an array. The array key is the id of the item (for example
categories[91], 91 is the ID of the category) all ID are not exactly in
date order, but they're added to the array in date order, how do I find
the previous (in the sense of when it was added) array entry of, for
example category['91']?

--

Belmin Fernandez

Visit: http://www.belminfernandez.com/homepage
Email: belminf at gmail period com

[JDS]

Re: Retrieving previous array item

On Wed, 23 Feb 2005 17:48:05 +0000, Belmin wrote:
[color=blue]
> I have an array. The array key is the id of the item (for example
> categories[91], 91 is the ID of the category) all ID are not exactly in
> date order, but they're added to the array in date order, how do I find
> the previous (in the sense of when it was added) array entry of, for
> example category['91']?[/color]

How are items added to the array? I don't understand how, if "all ID are
not exactly in date order," the items are added in date order.

In any case, any solutions based on your current array will be unreliable.

To make your data reliable, you will need to add the date to the data
somehow. I suggest a 2D associative array along the lines of

$categories = array(
array( "id" => 91, "date_added " => "2005-02-23 10:30:33" )
, array( "id" => 92, "date_added " => "2005-02-23 12:19:52")
);

(the time stamp can be formatted however you wish)

Then you can actually do stuff with the real date value and be certain
that it is correct in comparison to other items in the array.

--
JDS | jeffrey@example .invalid
| http://www.newtnotes.com
DJMBS | http://newtnotes.com/doctor-jeff-master-brainsurgeon/

[Geoff Berrow]

Re: Retrieving previous array item

I noticed that Message-ID:
<pan.2005.02.23 .18.30.18.58453 9@example.inval id> from JDS contained the
following:
[color=blue]
>How are items added to the array? I don't understand how, if "all ID are
>not exactly in date order," the items are added in date order.
>[/color]

Yeah, I wondered about that too...

--
Geoff Berrow (put thecat out to email)
It's only Usenet, no one dies.
My opinions, not the committee's, mine.
Simple RFDs http://www.ckdog.co.uk/rfdmaker/

[Belmin]

Re: Retrieving previous array item

What I meant to say, the ID's aren't in date order. So for example, ID
91 might actually be older than ID 10. And also, not all IDs are used so
an array could look like:

array[10]
array[91]
array[23]
array[49]
(and so on)

Though during creation, they're stacked in date order. Im not sure if
I'm being clear enough. What I ended up doing is doing an array_keys
function and going by the index of it's results. Is this the most
efficient way?

Written by "JDS" on 2/23/05 1:30p:[color=blue]
> On Wed, 23 Feb 2005 17:48:05 +0000, Belmin wrote:
>
>[color=green]
>> I have an array. The array key is the id of the item (for example
>>categories[91], 91 is the ID of the category) all ID are not exactly in
>>date order, but they're added to the array in date order, how do I find
>>the previous (in the sense of when it was added) array entry of, for
>>example category['91']?[/color]
>
>
> How are items added to the array? I don't understand how, if "all ID are
> not exactly in date order," the items are added in date order.
>
> In any case, any solutions based on your current array will be unreliable.
>
> To make your data reliable, you will need to add the date to the data
> somehow. I suggest a 2D associative array along the lines of
>
> $categories = array(
> array( "id" => 91, "date_added " => "2005-02-23 10:30:33" )
> , array( "id" => 92, "date_added " => "2005-02-23 12:19:52")
> );
>
> (the time stamp can be formatted however you wish)
>
> Then you can actually do stuff with the real date value and be certain
> that it is correct in comparison to other items in the array.
>[/color]

--

Belmin Fernandez

Visit: http://www.belminfernandez.com/homepage
Email: belminf at gmail period com

[Wayne]

Re: Retrieving previous array item

On Wed, 23 Feb 2005 19:28:14 GMT, Belmin <anonymous@nosp am.com> wrote:
[color=blue]
>What I meant to say, the ID's aren't in date order. So for example, ID
>91 might actually be older than ID 10. And also, not all IDs are used so
>an array could look like:
>
>array[10]
>array[91]
>array[23]
>array[49]
>(and so on)
>
>Though during creation, they're stacked in date order. Im not sure if
>I'm being clear enough. What I ended up doing is doing an array_keys
>function and going by the index of it's results. Is this the most
>efficient way?[/color]

Try the end() function.

[Chung Leong]

Re: Retrieving previous array item

"Belmin" <anonymous@nosp am.com> wrote in message
news:iP4Td.1328 4$qn2.2736440@t wister.nyc.rr.c om...[color=blue]
> Though during creation, they're stacked in date order. Im not sure if
> I'm being clear enough. What I ended up doing is doing an array_keys
> function and going by the index of it's results. Is this the most
> efficient way?[/color]

Nah, there isn't a efficient way to retrieve the previous item or index.
array_keys() followed by array_flip() is probably the most straight forward
way.

[Michael Fesser]

Re: Retrieving previous array item

.oO(Chung Leong)
[color=blue]
>"Belmin" <anonymous@nosp am.com> wrote in message
>news:iP4Td.132 84$qn2.2736440@ twister.nyc.rr. com...[color=green]
>> Though during creation, they're stacked in date order. Im not sure if
>> I'm being clear enough. What I ended up doing is doing an array_keys
>> function and going by the index of it's results. Is this the most
>> efficient way?[/color]
>
>Nah, there isn't a efficient way to retrieve the previous item or index.[/color]

prev() exists. Only problem is that you can't explicitly set the
internal array pointer to a particular element.

Micha