[RESOLVED] push_array and variable variables

[rhorne]

Hey guys,

As the title suggests I'm trying to use push_array with variable variables but having no such joy. Can anyone spot what I'm doing wrong here?

All I'm trying to do is loop through my arrays using the $x counter in my loop and add values to each array as we run through the loop.

Later I'll be creating queries to add different values to each array, but for now I'm just trying to get the basics work

//Set up our basic empty arrays
$month_1 = array();
$month_2 = array();
$month_3 = array();
$month_4 = array();
$month_5 = array();
$month_6 = array();
$month_7 = array();
$month_8 = array();
$month_9 = array();
$month_10 = array();
$month_11 = array();
$month_12 = array();

for ($x = 1; $x <= 13; $x++) 
{
	array_push($month_{$x},"1234","567890");
}

I've tried $month_$$x too and that doesn't seem to work either.

[rhorne]

Of course I realise my title should read array_push and not push_array.

[maxxd]

Give this a shot and let us know how it goes:

for($x = 1; $x <= 12; $x++)
{
    $arr = "month_{$x}";
    array_push($arr, '1234','567890');
}

edit I just realized you've only got 12 month arrays, so using <= 13 is going to throw an undefined variable error on the last iteration through the loop.

[rhorne]

Unfortunately that doesn't seem to be working either.

When I print the arrays they're still empty.

I think using your method, which actually makes perfect sense to me, when the array_push commands triggers, it's trying to push to an array called month_1 and month_2, which is close, but is not the variable array $month_1 $month_2.

[rhorne]

I even tried:

for($x = 1; $x <= 12; $x++) 
{ 
    $arr = "$" . "month_{$x}"; 
    array_push($arr, '1234','567890'); 
}  

But that didn't work, either.

[maxxd]

How weird. This works perfectly in an object, but not at all outside an object. For instance,

class Tester{
	private $month_1 = array();
	private $month_2 = array();
	private $month_3 = array();

public function testing(){
	for($x = 1; $x <= 3; $x++){
		$arr = "month_{$x}";
		array_push($this->$arr, '1234', '567890');
	}
}
public function results(){
	print("<p>\$month_1:</p><pre>".print_r($this->month_1, true)."</pre>");
	print("<p>\$month_2:</p><pre>".print_r($this->month_2, true)."</pre>");
	print("<p>\$month_3:</p><pre>".print_r($this->month_3, true)."</pre>");
}
}

$t = new Tester();
$t->testing();
$t->results();

gives the results you'd expect, but

$month_1 = array();
$month_2 = array();
$month_3 = array();

for($x = 1; $x <= 3; $x++){
	$arr = "month_{$x}";
	array_push($arr, '1234', '567890');
}

print("<p>\$month_1:</p><pre>".print_r($month_1, true)."</pre>");
print("<p>\$month_2:</p><pre>".print_r($month_2, true)."</pre>");
print("<p>\$month_3:</p><pre>".print_r($month_3, true)."</pre>");

throws errors. Strange.

[maxxd]

However,

$months = array(
	'month_1' => array(),
	'month_2' => array(),
	'month_3' => array(),
);
foreach($months as $idx=>$month){
	array_push($months[$idx], array('1234', '567890'));
}
print("<pre>".print_r($months, true)."</pre>");

does work, so that could be something you can use?

[rhorne]

That seems like it should do the trick. Thanks, maxxd. 🙂

It seemed a strange one because there was nothing particularly complex or revolutionary going on there, but combining variable variables with array_push just didn't seem to want to work.

[rhorne]

To expand further on this, using your example, if I want to insert specific values into one of the sub array, say month_5, how do I specifically target that?

[laserlight]

Frankly, you are grossly over-complicating this by naming your arrays separately and then trying to use variable variables. Using an array of arrays would be so much simpler, e.g.,

<?php

$months = array_fill(0, 12, array('1234', '567890'));
echo '<pre>';
print_r($months);
echo '</pre>';

rhorne wrote:

if I want to insert specific values into one of the sub array, say month_5, how do I specifically target that?

With an array of arrays, this becomes trivial, e.g.,

$months[4][] = 'whatever';

You can of course use array_push if you prefer.

EDIT:

rhorne wrote:

It seemed a strange one because there was nothing particularly complex or revolutionary going on there, but combining variable variables with array_push just didn't seem to want to work.

You just used incorrect syntax for the semantics that you were looking for. If you absolutely must use variable variables, then your loop should have been:

for ($x = 1; $x <= 12; $x++) 
{
    array_push(${'month_' . $x}, "1234", "567890");
}

But frankly, an array of arrays is simply better.

[rhorne]

I was using variable variables because I need to run two separate mysql queries to add data into my monthly arrays. 1234 and 567890 were just examples I was using to get the fundamental code working.

Longer term I'm doing a lot more with this as I'm populating some Highcharts graphs but I was just struggling with the syntax. Thanks for your help, I will try your revision shortly.

[laserlight]

rhorne wrote:

I was using variable variables because I need to run two separate mysql queries to add data into my monthly arrays.

That doesn't explain why an array of arrays will not suffice. Either way, you're basically associating a variable with a name and index to differentiate it from others in a list of such variables, so you might as well make use of the array syntax.

[rhorne]

I guess I was trying to work within what I was comfortable, and multidimensional arrays in the way you guys were so confidently talking about them were a little intimidating. I've been reading into them and practising for the last couple of hours, though, and I think I'm getting a handle on them.

Thanks again for your help.