Is it possible to remove a string (see example below) from a PHP array without knowing the index?
Example:
array = array("string1", "string2", "string3", "string4", "string5");
I need to remove string3.
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6 Answers
$index = array_search('string3',$array);
if($index !== FALSE){
unset($array[$index]);
}
if you think your value will be in there more than once try using array_keys with a search value to get all of the indexes. You'll probably want to make sure
EDIT:
Note, that indexes remain unchanged when using unset. If this is an issue, there is a nice answer here that shows how to do this using array_splice.
5 Comments
Zac Brown
I like this +1 for you. But, how can I confirm that it was removed (display on screen)?
GWW
Check out the php functions print_r and var_dump. You can use them to dump the contents of your array.
schellmax
note that using unset() will keep indexes untouched: stackoverflow.com/a/369761/176140
FluorescentGreen5
array_values is easier to use than array_splice for cleaning up the indexes.FluorescentGreen5
You should use
if($index) instead of if($index !== FALSE), it looks cleaner and still works. EDIT: NEVERMIND, it will not work if the string to be removed if it is on index 0.This is probably not the fastest method, but it's a short and neat one line of code:
$array = array_diff($array, array("string3"))
or if you're using PHP >5.4.0 or higher:
$array = array_diff($array, ["string3"])
2 Comments
FluorescentGreen5
I bench-marked you method against GWW's in a for loop that runs 2.5 million times. Your's completed in 18 seconds (17 seconds when I didn't use variables), whereas GWW's completed in 16 seconds. So
array_diff is slower as is deals with an array instead of a single string, causing overhead. If only there were a function like array_diff but for removing a single string in an array.
Tofandel
@FluorescentGreen5 slower but no that much slower, that's only about 5-10% difference which is not worth losing sleep over unless you deal with hundreds of thousands of records, and it might be even less in PHP8 now
You can do this.
$arr = array("string1", "string2", "string3", "string4", "string5");
$new_arr=array();
foreach($arr as $value)
{
if($value=="string3")
{
continue;
}
else
{
$new_arr[]=$value;
}
}
print_r($new_arr);
Comments
Use a combination of array_search and array_splice.
function array_remove(&$array, $item){
$index = array_search($item, $array);
if($index === false)
return false;
array_splice($array, $index, 1);
return true;
}
Comments
You can also try like this.
$array = ["string1", "string2", "string3", "string4", "string5"];
$key = array_search('string3',$array);
unset($array[$key]);
Comments
It sort of depends how big the array is likely to be, and there's multiple options.
If it's typically quite small, array_diff is likely the fastest consistent solution, as Jorge posted.
Another solution for slightly larger sets:
$data = array_flip($data);
unset($data[$item2remove]);
$data = array_flip($data);
But that's only good if you don't have duplicate items. Depending on your workload it might be advantageous to guarantee uniqueness of items too.
