echoing results of array_key_exists

[mpar612]

I have information stored in the $_SESSION['order'] array as $key => $value. Someone helped me construct the following code, but I cannot figure out how to get the contents of the array to populate the hidden form field. I would like to get it to where name=$key and value=$value.

Any thoughts?

Thanks in advance!

<?php
foreach ($itemsRows as $itemsRow) {
	if (array_key_exists ($itemsRow['itemId'], $_SESSION['order'])) {
		echo "<input type=\"hidden\" name=\" \" value=\" \" />";
	}
}
?> 

[laserlight]

I cannot figure out how to get the contents of the array to populate the hidden form field

Which array are you talking about?

I would like to get it to where name=$key and value=$value.

Therefore, identify the key and the value.

[laserlight]

I cannot figure out how to get the contents of the array to populate the hidden form field

Which array are you talking about?

I would like to get it to where name=$key and value=$value.

Therefore, identify the key and the value.

[mpar612]

Thanks for the response! I am checking to see if $itemRows['Id'] exists in the $_SESSION['order'] array. If it does I want to print a hidden form field. I tried the code below, but it won't work. I am having difficulty figuring out how to specify the values for $key and $value.

echo "<input type=\"hidden\" name=\"$key\" value=\"$value\" />";

[laserlight]

I think I understand. You want to do something like this:

<?php
foreach ($itemsRows as $itemsRow) {
    if (array_key_exists ($itemsRow['itemId'], $_SESSION['order'])) {
        echo '<input type="hidden" name="' . $itemsRow['itemId']
            . '" value="' . $_SESSION['order'][$itemsRow['itemId']] . '" />';
    }
}
?>

Note that you may wish to escape the variables being printed by using htmlspecialchars() or htmlentities().

[mpar612]

Maybe this will make it easier.

Here was my original code.

foreach ($_SESSION['order'] as $key => $value) {
	$found = false;

foreach ($itemsRows as $itemsRow) {
	if ($itemsRow['itemId'] == $key) {
		$found = true;
		break;
	}
}
        if (!$found) {
		echo "<input type=\"hidden\" name=\"$key\" value=\"$value\" />";
	}
}

I am trying to make my code more efficient and reduce the length of it by changing it to:

foreach ($itemsRows as $itemsRow) {
	if (array_key_exists ($itemsRow['itemId'], $_SESSION['order'])) {
		echo "<input type=\"hidden\" name=\"$key\" value=\"$value\" />";
	}
}

I have information stored in the $_SESSION['order'] array in $key=>$value format. I want to pull information from a database (the $itemsRow). If the information in the array is not in the results from the database I want to print the hidden input field. Not having the $key and $value from my first piece of code is confusing me. I am not sure how to specify this or how to properly do this.

Please let me know if you need further clarification. Thank you very much for your help!

[laserlight]

If the information in the array is not in the results from the database I want to print the hidden input field.

Ah, that changes things. You stated that you were "checking to see if $itemRows['Id'] exists in the $SESSION['order'] array" and if it does you wanted to print a hidden form field. Now you are saying that you are checking $SESSION['order'], and if the current key does not exist in $itemRows, you want to print a hidden form field. Which of these do you want?

[mpar612]

I'm sorry.

I want to check $_SESSION['order'], and if the current key does not exist in $itemRows, I want to print a hidden form field.

Thanks!

[laserlight]

It seems to me that your original code is fine, though you could simplify it to:

foreach ($_SESSION['order'] as $key => $value) {
    foreach ($itemsRows as $itemsRow) {
        if ($itemsRow['itemId'] == $key) {
            echo "<input type=\"hidden\" name=\"$key\" value=\"$value\" />";
            break;
        }
    }
}

The bad part is that you are retrieving all the rows for $itemsRows, and then looping over that potentially large result set on each iteration of the outer loop.

It may be possible to construct an SQL query that will eliminate this problem, though it may also depend on how you construct the $_SESSION['order'] array as well.

[mpar612]

I made one modification to your code. The third line should contain "!=" instead of "==". If I use your code it does not work. If I make that slight modification it prints a hidden input field for everything in the array.

I am going to be using this exact piece of code in multiple places, which is why I need this written as efficiently as possible.

Any thoughts would be greatly appreciated. Thanks!

foreach ($_SESSION['order'] as $key => $value) {
	foreach ($itemsRows as $itemsRow) {
		if ($itemsRow['itemId'] != $key) {
			echo "<input type=\"hidden\" name=\"$key\" value=\"$value\" />";
			break;
		}
	}
}

[laserlight]

I made one modification to your code. The third line should contain "!=" instead of "==". If I use your code it does not work. If I make that slight modification it prints a hidden input field for everything in the array.

Yes, that is a correct change.

I am going to be using this exact piece of code in multiple places, which is why I need this written as efficiently as possible.

Besides the possible macro optimisation involving rewriting the entire thing, you can cache the output in an array, then print out the array whenever you need to.

[mpar612]

But why is it printing out all of the items in the array and not just items in the array that do not equal the items being returned from the database?

Thanks!

[laserlight]

sigh

Sorry, I was not thinking correctly. My "improvement" is incorrect. Your original code is correct, except for the indentation:

foreach ($_SESSION['order'] as $key => $value) {
    $found = false;

foreach ($itemsRows as $itemsRow) {
    if ($itemsRow['itemId'] == $key) {
        $found = true;
        break;
    }
}

if (!$found) {
    echo "<input type=\"hidden\" name=\"$key\" value=\"$value\" />";
}
}

Unfortunately, it is slow, unless the arrays in question are small.

[mpar612]

Thanks! Wouldn't there be a way to use the array_key_exists method that would make it more efficient?

[laserlight]

Perhaps you can use this:

$itemIds = array();
foreach ($itemsRows as $itemsRow) {
    $itemIds[] = $itemsRow['itemId'];
}

foreach ($_SESSION['order'] as $key => $value) {
    if (!in_array($key, $itemIds)) {
        echo "<input type=\"hidden\" name=\"$key\" value=\"$value\" />";
    }
}

EDIT:
Empirical testing shows that the above code is a magnitude faster than the original, and should have the same result.