display multiple selection

[Tiger99]

I need to select multiple items in a selection
So, I have two arrays. One array contains all the item and the other array contains "Seleted" items

So how can loop those two arrays so that it display approprate selection?

What I have is the following
for($i=0; $i<$num_rows; $i++){
foreach($artist_id as $id){
if($artid[$i]==$id){
$display.="\n\t<option value='$id' selected>$artname[$i]";
}

		}
		$display.="\n\t<option value='$artid[$i]'>$artname[$i]";
	}

However, it display the selected item twice

Please help

Thanks in advance

[Weedpacket]

I think you'd be better off just having the one loop to run through all the items, and use in_array() to see which of them are selected.

[Tiger99]

I tried

if(in_array($needle_array, $haystack_array)){
}

[Tiger99]

continu.....

but I got an error message
Wrong datatype for first argument in call to in_array

Why can't I use array as the first argument?
I checked the doumentation, and it has an example of using first argument as array

???

Please Help

Thanks in advance

[tomhath]

I didn't see the example you mention. I thought there was a way to to this with regular expressions, but don't see that either.

I suppose you could merge the two arrays and count the elements. But it might still be easier to search one at a time. Here's a guess at a one-liner, untested:

while (list ($key, $val) = each (array_count_values(array_merge ($array1, $array2))) ) {
  if ($val > 1) { 
    ...
  }
}

[Tiger99]

This is the example from the documentation that I am talking about
Example 3. in_array() with an array as needle

<?php
$a = array(array('p', 'h'), array('p', 'r'), 'o');

if (in_array(array ('p', 'h'), $a))
echo "'ph' was found\n";
if (in_array(array ('f', 'i'), $a))
echo "'fi' was found\n";
if (in_array('o', $a))
echo "'o' was found\n";
?>

// This will output:

'ph' was found
'o' was found

Could you explain your code a little bit more detail, because I don't really understand what your code is doing

Thanks

[tomhath]

The example you gave looks like they are cheating a little, searching strings but calling them arrays. Where did you find that?

Here's a longer example like the one I gave before. The intermediate variable $array3 shouldn't be needed. But without it the "each" function never gets past the first array entry, looks like a bug in php. Run this and you'll see how it finds values that are in both arrays:

<?php 
$array1 = array("red", "white", "blue"); 
$array2 = array("green", "red"); 

echo "<PRE>";
print_r (array_merge ($array1, $array2) );
echo "</PRE>";

echo "<PRE>";
print_r (array_count_values(array_merge ($array1, $array2)));
echo "</PRE>";

$array3 = array_count_values(array_merge ($array1, $array2));

while ( list ($key, $val) = each ($array3) ) { 
 echo "key " . $key . " has a count of " . $val . "<br>";
}
?>

[Weedpacket]

Originally posted by Tiger99
but I got an error message
Wrong datatype for first argument in call to in_array

...which is why I said " one loop to run through all the items" - testing one item per iteration, in other words.

[Tiger99]

Hello Weedpacket

Could you please give an example of what you mean by " one loop to run through all the items" and how do you use in_array to do that. I am just a beginner. Appreciated

[Weedpacket]

You know how to write a loop that goes through all the element in an array. You did it twice in your iniitial question.

$smallints = array(1,2,3,4,5);
$smallprimes = array(2,3,5,7,11);

foreach($smallints as $smallint)
{ if(in_array($smallint, $smallprimes))
   echo "$smallint is a prime";
}