Only print array row data if id is found in a whitelist array [duplicate]

Question

I have a list of categories for my videos, and with this simple foreach loop, I'm displaying all of them inside hyperlinks.

Now, what I want to do is display only some of them, based on the category ID.

Code that display all the categories:

$idx = 0; foreach ($this->categories as $category) { echo "\n" . ($idx++ ? '| ' : '') . '<a href="' . KM_Helpers::getCategoryURL($category) . '">' . $category['name'] . '</a>'; }

Let's say now I want to display only the categories with the ids: 2,8,21,22. I can use $category['id'] to get the IDS.

I was thinking of having an array that contains only the ID I want to show...

$myarray = array(2, 8, 21, 22);

My question is, how can I loop in my $category array, displaying only the ID contained in the array? (Based on $category['id'] )

@Jleagle no. the first time it will return false. $idx++ returns the value of $idx before incrementing it. — Mark Reed
– Mark Reed, Commented Apr 26, 2012 at 14:22
All of the answers above are assuming that you are pulling the ID into the categories query. Are you doing that? @Surreal Dreams, I read the $category['id'] line more of a question not a statement. — Ryan B
– Ryan B, Commented Apr 26, 2012 at 14:25

Mark Reed · Accepted Answer · 2012-04-26 14:25:57Z

If the id value matches the index in the categories array, you can just loop over the ones you want:

foreach ($myarray as $id) { $category = $this->categories[$id]; echo "\n".($idx++ ? '| ' : '') . '<a href="' . KM_Helpers::getCategoryURL($category) . '">' . $category['name'] . '</a>'; }

Otherwise, you have to do a double-loop (possibly hidden by in_array), either to check if an id is valid or to find the category with a given valid id.

This is a slick way to approach the problem - iterate over the approved ids instead of iterating over the categories - less overhead. OP never mentions doing anything else that requires touching all the categories each time, so +1.

John Conde · Accepted Answer · 2012-04-26 14:14:33Z

$idx = 0; $myarray = array(2, 8, 21, 22); foreach($this->categories as $category) { if (!in_array($category['id'], $myarray)) { continue; // skip it if the id isn't in your array of accceptable IDs } echo "\n".($idx++ ? '| ' : '').'<a href="'.KM_Helpers::getCategoryURL($category).'">'.$category['name'].'</a>'; }

Surreal Dreams · Accepted Answer · 2012-04-26 14:16:25Z

Not a problem. Add in some simple logic to test if the id is on your list of "approved" ids:

$idx = 0; $myarray = array(2, 8, 21, 22); foreach($this->categories as $category) { if(in_array($category['id'], $myarray) { echo "\n".($idx++ ? '| ' : '').'<a href="'.KM_Helpers::getCategoryURL($category).'">'.$category['name'].'</a>'; } }

This tests the $category['id'] in each iteration of the loop and if it's in your array of ids, you echo the link. Otherwise the category item is ignored and the loop moves on.

472084 · Accepted Answer · 2012-04-26 14:21:50Z

$ids= array(2, 8, 21, 22); $idx = 0; foreach($this->categories as $id => $category){ if (in_array($category['id'] , $ids)) { echo "\n".($idx++ ? '| ' : '').'<a href="'.KM_Helpers::getCategoryURL($category).'">'.$category['name'].'</a>'; } }

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Only print array row data if id is found in a whitelist array [duplicate]

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