remove element from array

Anon

Is there an easy way to remove elements from an array?

I have an array and I need specific items to be removed based on the users choice.

Select box named 'remove_element[ ]'
Returns values selected in the select box

ie: remove_element[0] = foo
remove_element[1] = bar

$array = array("this","foo","that","bar","the other");

I need to remove 'foo' and 'bar' from $array so that:

$array = array("this","that","the other");

Is there a function that allows me to remove elements = to a value, or will it take the multiple nested loops I am thinking it will take?

Thanks

Anon

unset($array[1]);
unset($array[3]);

Anon

Thank you! May the Internet gods bless you with an IPO.

Anon

WARNING: unset($array[$element]) is not an efficient way to delete the element in an array. What that does is simply set its value to null. It's not like a linked list that will actually remove the element. Run this code and you'll see:

<?
$ar = array("this","that","foo","bar","the other");

$s=sizeof($ar);
for($i=0;$i<$s;$i++)
print "ar[$i] = " .$ar[$i]."\n";

unset($ar[1]);

print "\n";
for($i=0;$i<$s;$i++)
print "ar[$i] = " .$ar[$i]."\n";

OUTPUT:

ar[0] = this
ar[1] = that
ar[2] = foo
ar[3] = bar
ar[4] = the other

ar[0] = this
ar[1] =
ar[2] = foo
ar[3] = bar
ar[4] = the other

If I had not done $s=sizeof($ar), and instead just used sizeof($ar) in the for loop, the output would look like this:

ar[0] = this
ar[1] = that
ar[2] = foo
ar[3] = bar
ar[4] = the other

ar[0] = this
ar[1] =
ar[2] = foo
ar[3] = bar

So, you have to write a function that will reconstruct the array. Someone pasted it to me but I can't find it.

Mike

Anon

OK this is what I use:

<?
function array_del($array,$place) {
$newarray = array();
$n=0;
for ($i=0;$i<sizeof($array);$i++)
if ($i!=$place)
$newarray[$n++] = $array[$i];

return $newarray;
}

// example
// $ar = array(....);
array_del($ar,3);

Removes the elements of location 3 and builds the rest of the array. Pretty fast when I test it, and works for multidimensional arrays like:

$ar[0][id] = '34343243243242323';
$ar[0][val]= 3243243;
$ar[1][id] = 'asdgfay43543fasdf';
$ar[1][val] = 5564646;

Tell me what you think...

Mike
?>

Anon

i like your function but am tied up a bit. i am trying to remove stop words from a search query and am searching a table in the database containing these words.

i need to be able to remove multiple elements to build a new search string and the array_del function seems only to be able to remove one...

i have a seperate function that keeps track of the elements that need to be removed and am using those to send as the 'place' value. it removes each fine but when it goes back into the array_del it starts with the complete search string and removes another stopword and puts back the previously removed.

am i making sense??

i am trying to work it so i can send a place array to remove them all at once.

any ideas??

here's the loop sending the individual array elements to the function:

for ($i=0;$i<sizeof($stopword_array);$i++){
$new_search_array = array_del($search_array, $stopword_array[$i]);
}

Anon

Here is my version that is suited for removing an array element referenced by its value.

function array_del($old_array,$value)
{
foreach($old_array as $element)
{
if($element != $value)
$new_array[] = $element;
}
return $new_array;
}

Anon

Sorry, Nick. I dont thant to dissappoint you but there is such function as UNSET:

// destroy a single variable
unset ($foo);

// destroy a single element of an array
unset ($bar['quux']);

// destroy more than one variable
unset ($foo1, $foo2, $foo3);

danielle

but doesn't unset remove only the value of that leaving an empty element in the array?

Anon

Hi,
I was unable to use unset() on an array element to remove it and its storage space from the array. I am using PHP 4.0.4. Have you tested this successfully on a more recent version?

Nick

Anon

If you want to remove the whole element and not be left with an empty element, use array_splice. Like so...

$arr = array(a, b, c, d);
//now, to remove "c"...

array_splice($arr, 2, 1);

//the first "1" indicates the key in the array (i.e. 0,1,2,3), and the "1" is the length of the amount of array you want removed. (if you put 2 instead of 1, both c and d would be removed.

//and you get:

array (0 => "a", 1 => "b", 2 => "d")

Wow, I'm actually giving advice! Never thought it'd happen.
Good Luck,
Lucas