PHP - Using explode() function to assign values to an associative array

I'd like to explode a string, but have the resulting array have specific strings as keys rather than integers:

ie. if I had a string "Joe Bloggs", Id' like to explode it so that I had an associative array like:

$arr['first_name'] = "Joe";
$arr['last_name'] = "Bloggs";

at the moment, I can do:

$str = "Joe Bloggs";
$arr['first_name'] = explode(" ", $str)[0];
$arr['last_name'] = explode(" ", $str)[1];

which is inefficient, because I have to call explode twice.

Or I can do:

$str = "Joe Bloggs";
$arr = explode(" ", $str);
$arr['first_name'] = $arr[0];
$arr['last_na开发者_运维问答me'] = $arr[1];

but I wonder if there is any more direct method.

Many thanks.

I would use array_combine like so:

$fields = array ( 'first_name', 'last_name' );
$arr = array_combine ( $fields, explode ( " ", $str ) );

EDIT: I would also pick this over using list() since it allows you to add fields should you require without making the list() call unnecessarily long.

You can make use of list ^{PHP Manual} (Demo):

$str = "Joe Bloggs";
list($arr['first_name'], $arr['last_name']) = explode(" ", $str);

$arr then is:

Array
(
    [last_name] => Bloggs
    [first_name] => Joe
)

You cannot do explode(" ", $str)[0] in PHP <= 5.3.

However, you can do this:

list($arr['first_name'], $arr['last_name']) = explode(" ", $str);