How to keep variable value unchanged after function in php

php Steps to make variables unchanged through function values: 1. Define a function "modifyVariable", accept a parameter "$variable", and specify to pass it by reference; 2. Create a function named "$myVariable" variable and pass it to the "modifyVariable" function; 3. Use the "echo" statement to output the value of "$myVariable", and the output value is the "modified value".

The operating environment of this article: Windows 10 system, php8.1.3 version, dell g3 computer.

If you want to manipulate a variable in a function but keep its value unchanged, you can pass the variable as a parameter to the function. Here are the detailed steps:

Create a function that accepts parameters and operates on them. For example:

function modifyVariable(&$variable) {
    // 在函数中对变量进行操作，使用 '&' 符号表示通过引用传递
    $variable = "修改后的值";
}

Create a variable at the function call location and pass it to the function. Make sure to prepend the variable with the '&' sign so that it can be passed as a reference. For example:

$myVariable = "原始值";
modifyVariable($myVariableecho $myVariable; // 输出："修改后的值"

1. Define a function modifyVariable, which accepts a parameter $variable and specifies passing it by reference.

2. We create a variable called $myVariable and pass it to the modifyVariable function. The value of the function's internal parameter $variable is modified to the "modified value".

3. We use the echo statement to output the value of $myVariable, and you will see that it is output as "modified value".

Please note that when a variable is passed by reference, modifications to the variable within the function will also affect the value of the variable outside the function. That's why the value of $myVariable is modified after the function is executed.

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