PHP Callback Functions

PHP Callback Functions Tutorial

In PHP Callback Functions is a function that is passed as an argument to another function and is executed at a later time. Callbacks are useful for customizing behavior, array operations, or event handling.

1️⃣ Basic Callback Function

Output:

✅ array_map() applies the callback function to each element of the array.

2️⃣ Using Anonymous Functions as Callbacks

Output:

✅ Anonymous functions are convenient for inline callback logic.

3️⃣ Callback with usort() (Custom Sorting)

Output:

✅ usort() uses a callback to define custom sorting logic.

4️⃣ Using call_user_func()

call_user_func() calls a callback function dynamically:

Output:

5️⃣ Using call_user_func_array()

Allows calling a callback with an array of parameters:

Output:

6️⃣ Key Points About Callback Functions

1. A callback function can be:

   • Named function

   • Anonymous function

   • Static class method

2. Useful in:

   • array_map(), array_filter(), array_reduce()

   • Sorting arrays (usort(), uasort())

   • Event handling or dynamic function calls

3. call_user_func() and call_user_func_array() allow dynamic execution.