PHP AdvancedLesson 40Free preview

PHP Callback Functions

This lesson is part of PHP · All levels

Summary

A callback is a function that is continued as an argument to another function to be called in. This pattern is widely used in array functions such as array_walk(), usort(), and array_map(). You also know how to call a function by its name in the form of a string.

Key points

Callback is a function that is sent as an argument to run another function
The callback name can be written as a string or a closure.
Array_walk() and usort() receive callbacks to process array elements
Call_user_func() calls a function based on the name stored in the string

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