Avoid duplicate code in statements like: isset($_GET['foo']['bar']) ? $_GET['foo']['bar'] : NULL;

To read unknown variables in PHP often I use code like the following:

$bar = isset($_GET['foo']['bar']) ? $_GET['foo']['bar'] : NULL;

I don't like to write the variable name twice. It just looks ugly and is too long for such an everyday task.

Do you know a better solution? Just using the @ operator or suppress notices at all is no option (bad practice, slow).

With a custom function and variable by reference it is somehow possible:

function ifset(&$value)
{
    if(isset($value)) return $value;
}
$bar = ifset($_GET['foo']['bar']); // $_GET is empty

However this creates silently new unwanted variables with that name/path. A var_dump($_GET) would print:

array(1) {
  ["foo"]开发者_如何转开发=>
  array(1) {
    ["bar"]=>
    NULL
  }
}

Although this will not completely solve your problem, in some cases you can use extract($_GET);

<?php

/* Suppose that $var_array is an array returned from
   wddx_deserialize */

$size = "large";
$var_array = array("color" => "blue",
                   "size"  => "medium",
                   "shape" => "sphere");
extract($var_array, EXTR_PREFIX_SAME, "wddx");

echo "$color, $size, $shape, $wddx_size\n";

?>

Use : "eval(foo,bar") see in a php manual for: eval.

Another way to redesign your function would be to make a recursive function that adds all of the set keys into an array as names and then simply check using in_array() function. If found, return value.

Finally PHP7 brings a solution. Yeah! The coalesce operator.

$bar = $_GET['foo']['bar'] ?? NULL;

If the value before the ?? exists and is not NULL it returns that one, otherwise it takes the fallback value from behind the ??. I love it!