{"id":600,"date":"2021-03-23T03:08:11","date_gmt":"2021-03-23T03:08:11","guid":{"rendered":"https:\/\/phptutorial.net\/?page_id=600"},"modified":"2021-07-12T07:14:20","modified_gmt":"2021-07-12T07:14:20","slug":"php-namespace","status":"publish","type":"page","link":"https:\/\/www.phptutorial.net\/php-oop\/php-namespace\/","title":{"rendered":"PHP Namespace"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you’ll learn about PHP namespaces, how to define classes that belong to a namespace, and how to use namespaces.<\/p>\n\n\n\n

Why namespaces #<\/a><\/h2>\n\n\n\n

When your project grows in complexity, you’ll need to integrate the code from others. Sooner or later, you’ll find that your code has different classes<\/a> with the same name. This problem is known as name collision<\/strong>.<\/p>\n\n\n\n

To resolve it, you can use namespaces. PHP supported namespaces since version 5.3.<\/p>\n\n\n\n

What is a namespace #<\/a><\/h2>\n\n\n\n

It’s easier to understand namespaces by analogy to the directory structure in a filesystem.<\/p>\n\n\n\n

A directory stores related files, which is similar to a namespace that groups related classes.<\/p>\n\n\n\n

A directory doesn’t allow you to have two files with the same name. However, you can have files with the same names in different directories. Likewise, namespaces mimic the same principle.<\/p>\n\n\n\n

By definition, namespaces provide you with a way to group related classes and help you avoid any potential name collisions.<\/p>\n\n\n\n

Namespaces are not limited to group classes. They can group other identifiers, including functions<\/a>, constants<\/a>, variables<\/a>, etc.<\/p>\n\n\n\n

Set up a directory structure #<\/a><\/h2>\n\n\n\n

First, create a project directory, e.g., store<\/code> and create a new index.php<\/code> file in the directory.<\/p>\n\n\n\n

Second, create src<\/code> directory in the project directory and Model<\/code> directory in the src<\/code> directory.<\/p>\n\n\n\n

Third, create a new file called Customer.php<\/code> in the Model<\/code> directory with the following code:<\/p>\n\n\n

<?php<\/span>\n\nclass<\/span> Customer<\/span>\n<\/span>{\n    private<\/span> $name;\n\n    public<\/span> function<\/span> __construct<\/span>($name)<\/span>\n    <\/span>{\n        $this<\/span>->name = $name;\n    }\n\n    public<\/span> function<\/span> getName<\/span>()<\/span>\n    <\/span>{\n        return<\/span> $this<\/span>->name;\n    }\n}<\/span><\/code><\/span>Code language:<\/span> HTML, XML<\/span> (<\/span>xml<\/span>)<\/span><\/small><\/pre>\n\n\n
The directory looks like the following:<\/p>\n\n\n
.\n\u251c\u2500\u2500 index.php\n\u2514\u2500\u2500 src\n    \u2514\u2500\u2500 Model\n        \u2514\u2500\u2500 Customer.php<\/code><\/span>Code language:<\/span> plaintext<\/span> (<\/span>plaintext<\/span>)<\/span><\/small><\/pre>\n\n\n
Define a namespace #<\/a><\/h2>\n\n\n\n
To define a namespace, you place the namespace<\/code> keyword followed by a name at the very top of the page. The following example gives the Customer<\/code> class with a namespace Store\\Model<\/code>:<\/p>\n\n\n
<?php<\/span>\n\nnamespace<\/span> Store<\/span>\\Model<\/span>;\n\nclass<\/span> Customer<\/span>\n<\/span>{\n    private<\/span> $name;\n\n    public<\/span> function<\/span> __construct<\/span>($name)<\/span>\n    <\/span>{\n        $this<\/span>->name = $name;\n    }\n\n    public<\/span> function<\/span> getName<\/span>()<\/span>\n    <\/span>{\n        return<\/span> $this<\/span>->name;\n    }\n}<\/span><\/code><\/span>Code language:<\/span> HTML, XML<\/span> (<\/span>xml<\/span>)<\/span><\/small><\/pre>\n\n\n