5.4 dereferencing to valid 5.3 array call [duplica

问题:

This question already has answers here:

PHP syntax for dereferencing function result (22 answers)

Array dereferencing doesn't work [duplicate] (5 answers)

Closed 6 years ago.

I got an error on this line of code which uses dereferencing:

   $data['data'] = $results->result()[0];

(I started learning PHP with PHP 5.4.) How can I dereference in a 5.3 manner?

I have checked the docs:

function getArray() {
    return array(1, 2, 3);
}

// on PHP 5.4
$secondElement = getArray()[1];

// before PHP 5.4
$tmp = getArray();
$secondElement = $tmp[1];

// or
list(, $secondElement) = getArray();

but creating a method call seems cumbersome

回答1:

list() is what you want. It's been around forever and works great assuming the value on the right can be accessed by integer keys.

<?php
list(, $one, , $three) = range(0, 4);

Note that list() does not iterate the keys (as foreach would), but accesses integer keys by slot position (0, 1, ...) directly. If those keys don't exist you'll get a NOTICE and your value set to null.

回答2:

$res = $results->result();
$data['data'] = $res[0];

Or you can use reassignment (to avoid the need for temporary variables):

$data['data'] = $results->result();
$data['data'] = $data['data'][0];