How to determine whether the passed parameter is a variable?

Question

function is_var($var){//???How to write}$a = 123;var_dump(is_var($a));//true

var_dump(is_var('456')) ;//falsevar_dump(is_var(456));//falsevar_dump(is_var([1,2,3]));//false...

That is, pass the parameters directly If a value is written, false is returned. If a variable is defined, true is returned.

Is there any way? . .

飞天001 · Answer

Can I judge that the one with $ in front is a variable? I am a novice and I am just talking nonsense.

扬帆起航 · Answer

How can I edit a post without deleting it? . . . The first time I posted, it showed up in a mess. . .

扬帆起航 · Answer

function is_var($var){

//???How to write

}

$a =123;

var_dump(is_var ($a));//true

var_dump(is_var('456'));//false

var_dump(is_var(456));// false

var_dump(is_var([1,2,3]));//false

......

That is, if you pass the parameter and write the value directly, return false , if a variable is defined, return true

Is there any way? . .