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The concept of php function
PHP user-defined function
● In addition to the built-in PHP functions, we can create our own functions.
● Functions are blocks of statements that can be used repeatedly in a program.
● The function will not be executed immediately when the page is loaded.
● Functions will only be executed when called.
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Creating user-defined functions in PHP
User-defined functions are declared with the word " function" starts with:
Syntax
function functionName() { 被执行的代码; }
Note: Function names can start with letters or underscores (not numbers).
Note: Function names are not case sensitive.
Tip: The function name should reflect the task performed by the function.
In the following example, we create a function named "writeMsg()". An opening brace ({) indicates the beginning of a function's code, while a closing brace (}) indicates the end of the function. This function outputs "Hello world!". To call this function, just use the function name:
Instance
<?php function sayHi() { echo "Hello world!"; } sayhi(); // 调用函数 ?>
Output:
Hello world!
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