Question about PHP global variables

Ask the PHP global variable question? & Nbsp; I declare a global variable $ GLOBALS [& quot; x & quot;] = 1; & nbsp; in 1. in php, redefine $ GLOBALS [& quot; x & quot;] = 2; & nbsp; in 2. in php, can I ask about PHP global variables?

I declare a global variable $ GLOBALS ["x"] = 1;
Redefine $ GLOBALS ["x"] = 2 in 1. php;
In 2.php, the result of $ GLOBALS ["x"] is still 1;

My idea is that there is a global variable. if it is modified, its value will be subject to the newly modified value. I don't know how to deal with it in PHP?

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1. php
Session_start ();
$ _ SESSION ['x'] = 1;

2. php
Session_start ();
$ _ SESSION ['x'] = 2;

3. php
Session_start ();
Echo $ _ SESSION ['x'];




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You use
Global $ x = 1;
Global $ x = 2;
Echo $ x;
Try

Unlike $ GLOBALS ['x '];
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$ GLOBALS ["x"] = 1; // temporary global variable. It is not a global variable in a session. So B. php shows 1
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Global variables are only valid in the same PHP file. sessions are required for different php files.
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Only sessions can access each other on each page!

The variables defined or accessed by gloabl and $ GLOBALS are all variables on this page!

To access variables in other files, you need to load the file!

There is a fundamental difference with session!