Errors when using array_push — "First argument should be an array"
Question by Nate
I have the following code:
<?php
function foo($bar)
{
global $products;
//$products = array();
$query = 'SELECT p_name FROM 0_products WHERE p_category IN (' . $bar . ')';
$results = mysql_query($query);
while($row = mysql_fetch_array($results, MYSQL_ASSOC))
{
array_push($products, $row);
echo 'name pushed, ';
}
}
require('mysql_ipb_connect.php'); // connect to ipb mysql database
$products = array();
foo(5);
?>
When I run it I get the following output:
Warning: array_push() [function.array-push]: First argument should be an array in /home/rgcpanel/public_html/category/category.php on line 14
name pushed,
Warning: array_push() [function.array-push]: First argument should be an array in /home/rgcpanel/public_html/category/category.php on line 14
name pushed,
Warning: array_push() [function.array-push]: First argument should be an array in /home/rgcpanel/public_html/category/category.php on line 14
name pushed,
If I uncomment “$products = array();” then the output is correct:
name pushed, name pushed, name pushed,
Why is this happening? I declare the $products array outside of a function (so it’s global), and then specify it as being a global inside the function. Something is not right, but I’m not sure what that is?
Thanks for your advice.
Answer by Michael Berkowski
Per the comments, $products was initialized by an included file which was included inside a function. That defines its scope to the function, rather than globally. So you’ll need to use global $products; before calling the include.
function func_that_defined_products() {
global $products;
include('file_that_defines_products.php');
}
// Now when called globally later, it will be at the correct scope.
function foo($bar)
{
global $products;
$query = 'SELECT p_name FROM 0_products WHERE p_category IN (' . $bar . ')';
// etc...
}
In any case, I find it a little more readable to use $GLOBALS['products'] instead of the global keyword. And as always, wherever possible it is a preferred practice to pass the variable into a function rather than accessing it globally.
// If you can, do it this way
function foo($bar, $products) {
// $products was a param, and so global is unnecessary
}
However in your case, if the CMS defines it you may lose the flexibility to do it that way…
Answer by Starx
