What is the mechanism for PHP function parameter type conversion?

The function parameter type conversion mechanism in PHP converts the type of the incoming parameters to be consistent with the function definition, including: integer parameters: string converted to integer floating point parameters: string converted to floating point Boolean parameters: specific Values ​​are converted to boolean array parameters: any type is converted to array object parameters: any value is converted to the specified object

PHP function parameter type conversion mechanism

The meaning of type conversion

Function parameter type conversion in PHP refers to converting the type of the incoming parameter to the type declared in the function definition when the function is called Consistent process. This helps ensure that the function's parameter values ​​are of the correct type and prevents unexpected errors.

Type conversion rules

PHP’s type conversion rules are as follows:

• Integer parameters:Incoming When the parameter is a string, PHP will try to convert it to an integer. If the string contains a valid integer, the conversion succeeds; otherwise, the conversion fails and the parameters are left intact.
• Floating point parameters: Similar to integer parameters, PHP will try to convert the incoming string to a floating point type.
• Boolean parameters: PHP Convert the following values ​​to Boolean values ​​true: empty string, 0, Boolean value false, string" false". All other values ​​are converted to false.
• Array parameters: If the function is defined to accept an array parameter, any type of parameter passed in will be converted to an array.
• Object parameters: If the function is defined to accept an object parameter, any value passed in will be converted to an object of that type.

Code Example

The following is a practical case showing parameter type conversion in PHP:

function sum($a, $b) {
  // 将 $a 转换为整型，将 $b 转换为浮点型
  $a = (int) $a;
  $b = (float) $b;
  
  // 返回两个参数的和
  return $a + $b;
}

$result = sum('5', '10.5');
echo $result; // 输出：15.5

In this example, sum() The function defines two integer parameters. When calling sum(), the first parameter passed in is a string, and the second parameter is a floating point type. Inside the function, we convert the first parameter to an integer and the second parameter to a float, and then add them together to get the final result of 15.5.

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