{"id":538,"date":"2021-03-20T01:00:25","date_gmt":"2021-03-20T01:00:25","guid":{"rendered":"https:\/\/phptutorial.net\/?page_id=538"},"modified":"2025-04-07T11:40:03","modified_gmt":"2025-04-07T11:40:03","slug":"php-__tostring","status":"publish","type":"page","link":"https:\/\/www.phptutorial.net\/php-oop\/php-__tostring\/","title":{"rendered":"PHP __toString"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you will learn how to use the PHP __toString()<\/code> method to return the string representation of an object.<\/p>\n\n\n\n

Introduction to the PHP __toString() method #<\/a><\/h2>\n\n\n\n

The __toString()<\/code> is one of a magic method in PHP. The following shows the syntax of the __toString()<\/code> method:<\/p>\n\n\n

public<\/span> function<\/span> __toString<\/span> ( )<\/span> : string<\/span><\/span><\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
The __toString()<\/code> method accepts no parameter and returns a string.<\/p>\n\n\n\n
When you use an object as it were a string, PHP will automatically call the __toString()<\/code> magic method. If the method doesn’t exist, PHP raises an error.<\/p>\n\n\n\n
The following example defines the BankAccount<\/code> class, creates a new instance of the BankAccount<\/code>, and display it:<\/p>\n\n\n
<?php<\/span>\n\nclass<\/span> BankAccount<\/span>\n<\/span>{\n\tprivate<\/span> $accountNumber;\n\n\tprivate<\/span> $balance;\n\n\tpublic<\/span> function<\/span> __construct<\/span>(\n\t\t$accountNumber,\n\t\t$balance\n\t)<\/span> <\/span>{\n\t\t$this<\/span>->accountNumber = $accountNumber;\n\t\t$this<\/span>->balance = $balance;\n\t}\n}\n\n$account = new<\/span> BankAccount('123456789'<\/span>, 100<\/span>);\necho<\/span> $account;<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
PHP raises the following error:<\/p>\n\n\n
PHP Fatal error:  Uncaught Error: Object of class BankAccount could not be converted to string...<\/code><\/span>Code language:<\/span> plaintext<\/span> (<\/span>plaintext<\/span>)<\/span><\/small><\/pre>\n\n\n
To use the $account<\/code> object as a string, you need to implement the __toString()<\/code> method that returns the string representation of the BankAccount<\/code> object. For example:<\/p>\n\n\n
<?php<\/span>\n\nclass<\/span> BankAccount<\/span>\n<\/span>{\n\tprivate<\/span> $accountNumber;\n\n\tprivate<\/span> $balance;\n\n\tpublic<\/span> function<\/span> __construct<\/span>(\n\t\t$accountNumber,\n\t\t$balance\n\t)<\/span> <\/span>{\n\t\t$this<\/span>->accountNumber = $accountNumber;\n\t\t$this<\/span>->balance = $balance;\n\t}\n\n\tpublic<\/span> function<\/span> __toString<\/span>()<\/span>\n\t<\/span>{\n\t\treturn<\/span> \"Bank Account: $this->accountNumber. Balance: $$this->balance\"<\/span>;\n\t}\n}\n\n\n$account = new<\/span> BankAccount('123456789'<\/span>, 100<\/span>);\necho<\/span> $account;<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
In this example, the __toString()<\/code> returns a string that contains the bank account number and its current balance. Here is the output:<\/p>\n\n\n
Bank Account: 123456789. Balance: $100<\/code><\/span>Code language:<\/span> plaintext<\/span> (<\/span>plaintext<\/span>)<\/span><\/small><\/pre>\n\n\n
Note that you can use the BankAccount<\/code> object anywhere that accepts a string. For example, you can concatenate a string with the BankAccount<\/code> object like this:<\/p>\n\n\n
$account = new<\/span> BankAccount('123456789'<\/span>, 100<\/span>);\n\necho<\/span> 'Bank information:'<\/span> . $account;<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
Bank information:Bank Account: 123456789. Balance: $100<\/code><\/span>Code language:<\/span> plaintext<\/span> (<\/span>plaintext<\/span>)<\/span><\/small><\/pre>\n\n\n
Returning value #<\/a><\/h2>\n\n\n\n
In PHP 7.4, the __toString()<\/code> method must return a string, otherwise PHP will throw an Error.<\/p>\n\n\n\n
The following example defines the Quarter<\/code> class that represents the quarter of the year. It implements the __toString()<\/code> method that returns a number:<\/p>\n\n\n
<?php<\/span>\n\nclass<\/span> Quarter<\/span>\n<\/span>{\n\tprivate<\/span> $number;\n\n\tpublic<\/span> function<\/span> __construct<\/span>($number)<\/span>\n\t<\/span>{\n\t\tif<\/span> ($number < 0<\/span> && $number > 4<\/span>) {\n\t\t\tthrow<\/span> new<\/span> InvalidArgumentException('Quarter must be between 1 and 4'<\/span>);\n\t\t}\n\t\t$this<\/span>->number = $number;\n\t}\n\n\tpublic<\/span> function<\/span> __toString<\/span>()<\/span>\n\t<\/span>{\n\t\treturn<\/span> $this<\/span>->number;\n\t}\n}\n\n$quarter = new<\/span> Quarter(1<\/span>);\necho<\/span> $quarter;<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
PHP raises the following error:<\/p>\n\n\n
Fatal error: Uncaught Error: Method Quarter::__toString() must return a string value<\/code><\/span>Code language:<\/span> plaintext<\/span> (<\/span>plaintext<\/span>)<\/span><\/small><\/pre>\n\n\n
PHP doesn’t coerce the number to a string in this case.<\/p>\n\n\n\n
In PHP 8, you’ll get the same error. However, if you disable the strict typing, PHP will coerce the return value to a string value. <\/p>\n\n\n\n
To disable the strict type, you the following statement:<\/p>\n\n\n
declare<\/span>(strict_types=0<\/span>);<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
The following example works on PHP 8 with strict typing is disabled:<\/p>\n\n\n
<?php<\/span>\n\ndeclare<\/span>(strict_types=0<\/span>);\n\nclass<\/span> Quarter<\/span>\n<\/span>{\n\tprivate<\/span> $number;\n\n\tpublic<\/span> function<\/span> __construct<\/span>($number)<\/span>\n\t<\/span>{\n\t\tif<\/span> ($number < 0<\/span> && $number > 4<\/span>) {\n\t\t\tthrow<\/span> new<\/span> InvalidArgumentException('Quarter must be between 1 and 4'<\/span>);\n\t\t}\n\t\t$this<\/span>->number = $number;\n\t}\n\n\tpublic<\/span> function<\/span> __toString<\/span>()<\/span>\n\t<\/span>{\n\t\treturn<\/span> $this<\/span>->number;\n\t}\n}\n\n$quarter = new<\/span> Quarter(1<\/span>);\necho<\/span> $quarter;<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Summary #<\/a><\/h2>\n\n\n\n
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  • Implement the __toString()<\/code> magic method to create the string representation of an object.<\/li>\n\n\n\n
  • The __toString()<\/code> method must return a string value or PHP raises an error.<\/li>\n<\/ul>\n
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Try it<\/a><\/p>\n\n\n\n