Properties for getter and setter in PHP?

Question

Yii

I read www.yiiframework.com/doc-2.0/guide-concept-propert...
I can't understand, but always the properties with which getters and setters work must begin with "_" ?
And if so, is this an OOP feature in php or a specific framework?

Answer 1

I can be wrong, but in my opinion, in the days of php 4, private methods and properties were named with the first character _, for ease of understanding.

Answer 2

Naming properties with an underscore is the wrong way, which for reasons unknown to me is followed by yii2 code-style ( https://github.com/yiisoft/yii2-coding-standards). There it is proposed to use underlining for all private variables.
the name of a variable and property should not reflect its scope, but only the assignment in the current context (method, block, closure, loop, etc.). Everything else is extra knowledge about the context, which makes the variable more "bound".

Answer 3

This is a feature of Yii, related to the fact that getters and setters are called using "magic" methods when accessing an attribute

Answer 4

I can’t understand, but always the properties with which getters and setters work must begin with "_"?

It's just poor quality code left over from the days of PHP4.
The PHP standards (PSR) forbid such naming.
PSR-2: 4.2. Properties

Property names SHOULD NOT be prefixed with a single underscore to indicate
protected or private visibility.