Kipengele cha Kuunganisha na null katika PHP
Wacha tuchunguze msimbo ufuatao:
<?php
if (isset($arr['test'])) {
$elem = $arr['test'];
} else {
$elem = 'empty';
}
?>
Msimbo huu unaweza kuandikwa tena kwa kutumia kipengele cha ternary:
<?php
$elem = isset($arr['test']) ? $arr['test'] : 'empty';
?>
Hata hivyo, toleo la kwanza la msimbo, na la pili,
zinasababisha usumbufu fulani. Ili kurahisisha
miundo kama hii, kipengele cha kuunganisha na null kilibuniwa,
kinachowakilisha
amri ??. Wacha tuandike tena msimbo wetu
kupitia kipengele hiki:
<?php
$elem = $arr['test'] ?? 'empty';
?>
Andika tena msimbo ufuatao kupitia kipengele kilichosomwa:
<?php
$user = ['name' => 'john', 'age' => 30];
if (isset($user['name'])) {
$name = $user['name'];
} else {
$name = 'unknown';
}
?>
