PHP little knowledge record

Three mesh operation

$a ? $a : $b Equivalent to $a ?: $b

$a ?? $b Equivalent to isset($a) ? $a : $b

An array of deconstruction

$str = "james:29";

[$name,$age] = explode(':',$str);

amount to list($name,$age) = explode(':',$str)

You can exchange the values of two variables ：[$a,$b] = [$b,$a]

Replace with array if Judge

$type = 'one';
//if How to write it 
if($type=='one'){
    $res = 100;
}else if($type=='two'){
    $res = 200
}else if($type=='three'){
    $res = 300
}


// Array writing 
$res = [
    'one' => 100,
    'two' => 200,
    'three' => 300,
][$type];

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