php null replacement function - php

Question

there is this function called Nz() in visual basic for application. the function checks variable nullity and returns a provided value if it finds the variable is null.
i try to write the same function in php, which looks like below:
function replace_null($value, $replace) {
if (!isset($value)) {
return $replace;
} else {
return $value;
}
}
$address = replace_null($data['address'], 'Address is not available.');
of course, if $data['address'] is found null, php will stop executing the code and replace_null won't be called.
i'm currently using ternary
(isset(data['address']) ? data['address'] : 'Address is not available.');
but i think replace_null, if it works, will offer a more convenient way.
is there a function in php that provide the same functionality as vba's Nz()?
any suggestion will be appreciated.
thanks in advance.

Answer 1

A bit roundabout: If you only use this to check for array members, you could pass the key separately:
function get_with_default($arr, $key, $defval)
{
return isset($arr[$key]) ? $arr[$key] : $defval;
}
If the variable could be set but null (Edit: which it cannot, thanks #deceze), add another check:
function get_and_coalesce_with_default($arr, $key, $defval)
{
return (isset($arr[$key]) && !is_null($arr[$key]) ? $arr[$key] : $defval;
}
As pointed out, isset() only succeeds on non-null values, so the above doesn't add anything. We can write a non-trivial check with array_key_exists, though:
function get_with_default_v2($arr, $key, $defval)
{
return (array_key_exists($key, $arr) && !is_null($arr[$key]) ? $arr[$key] : $defval;
}

Answer 2

You could pass the array and the key separately like this:
function valueOrDefault($array, $key, $default) {
return isset($array[$key]) ? $array[$key] : $default;
}
$address = valueOrDefault($data, 'address', 'Address is not available.');

Answer 3

If you pass by reference, PHP won't error out:
function Nz(&$var, $def='') {
return isset($var) ? $var : $def;
}
http://php.net/manual/en/language.references.pass.php

Answer 4

If the variable is declared you do something like $value?:$replace

Answer 5

function replace_null($value='', $replace='') {
if (!isset($value)) {
return $replace;
} else {
return $value;
}
}
Try this. It will allow you to call the function with or without passing parameters.

Answer 6

<?
function replace_null($value, $replace) {
if(empty($value) && $value !== '0') {
return $replace;
} else {
return $value;
}
}
$address = replace_null("0", "replacing null");
echo $address;
?>

Answer 7

I think using the is_null function would be much more useful:
$address = $data['address'];
if ( is_null($address) ) $address = 'Address is not available.';
If you really want this as a function:
function replace_null($value, $replace) {
if (is_null($value)) return $replace;
return $value;
}
$address = replace_null($data['address'], 'Address is not available.');