PHP Build a Basic PHP Website Listing and Sorting Inventory Items Creating the Display Function

Trevor Jones
Trevor Jones
1,961 Points

Please help me understand the logic of "as $id => $item" when declaring our function in foreach loop.

It was around the 3 minute mark of the video "Creating the Display Function." She is doing this so that we get our item id, or key. I understand the purpose.

I'm trying to understand the logic. What exactly does "$id => $item" do that allows it to run the item's key as well as the value of $item? She doesn't really say what the code is doing, she's more saying what it will do.

Thank you

4 Answers

I might be misunderstanding what you're asking, but I'll give it a shot. (I am also not someone who knows exactly all the behind the scenes, so this is my best guesswork).

$arr = array ("key1" => "value1", "key2" => "value2");
foreach($arr as $key=>$value) {
echo $key;
echo $value;

Looking above, PHP runs through the code, grabs the array, then starts the loop. PHP sees the associative, or => symbol, between the two variables, which it then places the pairing as the key=>value.

It does it this way because that's what the foreach loop expects, either just the value, or the key=>value pairing.

Jerry Schrader
Jerry Schrader
4,396 Points

SO in other words, you are saying that ($id, $item) is the same as (key, value) ?

Robert Leonardi
Robert Leonardi
17,151 Points

You can rename to anything foreach($catalog as $key => $value) and foreach($catalog as $mySpecialKey => $mySuperSpecialValue) are both the same... just make sure within that foreach, you are using the same variable name you created accordingly.

In this video , she basically separating the display function so that it can be used in different/multiple pages.

What the function does is:

  1. Taking the $id and $value as the arguments
  2. Runs these arguments inside its function (the foreach)
  3. Stores it in $output
  4. Return $output

FYI, step 3 is actually NOT necessary. You can directly return "<td>..... </td><td>..... </td><td>..... </td>";

17,744 Points

Hi Trevor,

I had trouble understanding and posted a question on this as well. In as simple terms as possible, $id is the key and $item is the value. For me this is confusing, but it is what was used in in the lesson.

I would have written it differently like this....

foreach($catalog as $key => $value) {
     // some code here;