String equality and deletion of variables in php

$a='11';
$b=11;
if($a===$b)
{
 echo 'strict equality';
}
else if($ a==$b)
{
 echo 'equal';
}
else
{
 echo 'not equal';
}

The results are equal.

Here’s how to delete elements in an array:

Examples are as follows:

$_POST=array("firstname"=>'f',"lastname"=>'j',"email"=>"fj@qq.com", "password"=>"123",'rpassword'=>"123");
 $user=$_POST;
 function deletearray($user)
 {
 foreach($user as $key => $value )
 {
 if($key=='firstname')
 {
 unset($user[$key]);
 }
 else
 {
 return true;
 }
 }
 }
 deletearray($user);
 print_r($user);

Remarks: At first I couldn't delete firstname. I always thought it was an error with ==. Later I found out that an error occurred when calling the function. If you want to change the incoming array, you should pass in &$user. That is, pass in Only by inserting a reference can the result of the array be changed.