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In this issue, the editor will bring you about how to solve the problem that php global variables can not be used in the function. The article is rich in content and analyzes and describes for you from a professional point of view. I hope you can get something after reading this article.

Solution: 1, use the global keyword to import global variables in the function, syntax "global global variable 1, global variable 2,..."; 2, use the super global variable "$GLOBALS" to access the specified global variable, syntax "$GLOBALS ['global variable name']".

Operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

In general, global variables cannot be used within a function, but sometimes we have to use global variables within a function. What should we do?

PHP provides two workarounds: the global keyword and the $globals hyperglobal variable.

Method 1. Use the global keyword

Take a look at the output as follows:

$a = 1$ b = 2$ c = 3

Analysis:

The function of the global keyword is to import global variables, using global variable 1, variable 2,. In the form of global variable 1, variable 2. When imported into the local scope of a function, global variables defined outside the function can be used inside the function.

There are a few points to pay attention to when using the global keyword:

The global keyword can only be used inside the function, not outside the function.

The global keyword can only be used to refer to global variables outside the function, and cannot be assigned directly when referencing. Assignment and declaration statements need to be written separately.

When a variable modified with the global keyword is destroyed inside the function, the variables outside the function are not affected.

Method 2: use the $Globals hyperglobal variable

The output is as follows:

$a = 1$ b = 2$ c = 3

Analysis:

GLOBALS is a predefined variable (also known as a hyperglobal variable), which is a global combinatorial array of all variables. The name of the variable is the key of the array, and you can access the specified global variable in the form of $GLOBALS ['variable name']. As long as it is a global variable that has appeared, it can be obtained through the array of $GLOBALS.

The difference between global and $GLOBALS

Global can only be used inside the function, not outside the function, while $GLOBALS can be used anywhere in the program (inside or outside the function).

When a variable decorated with the global keyword is destroyed inside the function, the variables outside the function are not affected; $GLOBALS is affected.

Reason:

When you modify the $var variable with the global keyword, it is a reference to the variable of the same name outside the function, and the inside and outside are two variables that do not affect each other.

And $GLOBALS ['var'] refers to the variable itself outside the function, which is a variable.

The above is the editor for you to share how to solve the problem that php global variables can not be used in the function, if you happen to have similar doubts, you might as well refer to the above analysis to understand. If you want to know more about it, you are welcome to follow the industry information channel.

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