Understanding and Application of Classes in PHP [2]_PHP Tutorial

Understanding and Application of Classes in PHP [2]

Many PHP enthusiasts feel that it is difficult to understand and master the concept of classes in PHP during the learning process. Although they know that classes exist for a reason, However, since there are few opportunities to come into contact with and use it, I will just skip it. In fact, as long as we understand the basic concepts of PHP such as variables and functions, it will not be a problem to grasp the meaning of classes. In view of the important role of classes in PHP, this article will introduce the concepts and applications of classes in PHP with specific examples.
 
 
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 The so-called class refers to a collection composed of variables and functions that act on the variables. Classes provide a way to describe things in the real world. By effectively using classes, we can combine multiple variables and functions that describe the same object and use them as a whole, making the written program more intuitive, more reasonable, and easier to maintain.

To give a more popular example, we can create a class named Bike to describe a bicycle in real life. First, we set the variables in this class to include $pedals, $chain, $front wheel, $rear wheel, $brakes, and $handle. Then, we create functions such as Stop(), Accelerate(), TurnLeft() and TurnRight(). In this way, we have a class that can describe all the behaviors and properties of the bicycle object. For example, we can pass the $front wheel and $rear wheel variables into the TurnLeft() function to get some kind of output.
Some people may ask the above examples, although it is interesting, but we can use conventional variables and functions to implement the same function. Why must we insist on using such a cumbersome class? Of course, if we only need to describe a bicycle in the script, there seems to be no special value in defining a class. But what if the script needs to involve multiple bikes? If we still adopt the conventional method of defining variables and functions for each bicycle, then just tracking each variable and ensuring that the correct variable is entered into the correct function is a quite complicated task. On the contrary, if you use a class approach, you can effectively reduce the number of required variables. In addition, a defined class can also be included in other files or scripts, thereby enabling code reuse.
 
 
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 After understanding the concept of PHP classes, let’s take a closer look at how to create and use classes in scripts.

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