How to call a PHP function from a string stored in a variable

A guide on how to call a PHP function from a string stored in a variable using PHP’s dynamic function call feature. This article will show you how to do it with illustrative examples.

In this article, we will explore how to call a PHP function when its name is stored as a string in a variable. PHP supports dynamic function calls, allowing you to execute a function by using its name stored in a variable.

PHP Code

<?php
// Define some functions
function sayHello() {
    echo "Hello, World!";
}

function greet($name) {
    echo "Hello, " . $name . "!";
}

// Call function from a string stored in a variable
$functionName = 'sayHello';
$functionName(); // Output: Hello, World!

// Call function with parameters from a string stored in a variable
$functionNameWithParam = 'greet';
$functionNameWithParam('John'); // Output: Hello, John!
?>

Detailed explanation:

function sayHello() {...}: Defines a simple function that displays "Hello, World!".
function greet($name) {...}: Defines a function with a parameter that displays "Hello" with the user's name.
$functionName = 'sayHello';: Stores the function name in the $functionName variable.
$functionName();: Calls the function using the name stored in the variable.
$functionNameWithParam = 'greet';: Stores the function name with parameters in the $functionNameWithParam variable.
$functionNameWithParam('John');: Calls the function with a parameter, outputting "Hello, John!".

System requirements:

PHP 7.0 or higher

How to install the libraries needed to run the PHP code above:

No additional libraries are required, only a basic PHP environment.

Tips:

Make sure the function name is valid and defined before calling it.
Use is_callable() to check if the function can be called before invoking it.

Tags: PHP, Function

How to extract numbers from a string in PHP

This article demonstrates how to extract numbers from a string in PHP using various methods such as regex (regular expressions), built-in functions like `preg_match_all`, `filter_var`, and manual approaches.

Example of Strategy Pattern in PHP

A guide on the Strategy Pattern in PHP with a concrete example, explaining how to implement and use this design pattern in object-oriented programming.

Update multiple columns in MySQL using PHP

A guide on how to update multiple columns in MySQL using PHP. This PHP code uses the UPDATE statement to change multiple column values in a MySQL database.

Update data in MySQL with PHP using Prepared Statements to Prevent SQL Injection

Guide on using Prepared Statements in PHP to update data in MySQL securely and efficiently. This PHP code helps prevent SQL Injection vulnerabilities when working with databases.

Guide to uploading multiple images in PHP

A detailed guide on how to upload multiple images at once in PHP, including file handling, format checks, and storage on the server.

Get the last character of a string in PHP

Guide on how to use PHP to get the last character of a string. This PHP code helps in easily retrieving the final character of a text string in string manipulation operations.

Multithreading in PHP using the pthreads library

A comprehensive guide on how to implement multithreading in PHP using the `pthreads` library. This article covers installation steps, examples, and how to use multithreading to improve PHP application performance.

Update data in MySQL using PHP

A guide on how to update data in MySQL using PHP. This code uses the UPDATE SQL statement to change information in a MySQL database efficiently.

Comprehensive guide to concatenating strings in PHP

A detailed guide on all the ways to concatenate strings in PHP, including the concatenation operator, string functions, and other methods.

How to check for a substring in a string in PHP

A guide on how to use the `strpos` function in PHP to check if a substring exists within a larger string. This is a simple and efficient way to handle string operations in PHP.