A Practical Guide to PHP Type Conversion: Solving Data Conversion Challenges

PHP Type Conversion Guide: Built-in conversion functions: settype(), intval(), floatval(), boolval() Custom conversion: cast operators (int), (float), (bool), (array) , (object) Practical case: Convert the value of the database result set from a string to an appropriate type, such as an integer

PHP Type Conversion Practical Guide

Type conversion is to convert one data type to another data type in PHP. This is useful when dealing with user input, database operations, and data conversion issues.

Built-in conversion functions

PHP provides several built-in functions to convert types:

• settype() - Convert the type of a variable
• intval() - Convert a string to an integer
• floatval() - Convert a string to a floating point number
• boolval() - Convert a string to a boolean value

Example:

// 将字符串转换为数字
$number = (int) "123";

// 将数字转换为字符串
$str = (string) 123;

// 将布尔值转换为字符串
$status = (string) true; // "1"

Custom conversions

For more complex conversions, you can perform custom conversions by explicitly using the cast operator:

• (int) - Convert to integer
• (float) - Convert to floating point number
• (bool) - Convert to boolean
• (array) - Convert to array
• (object) - Convert to object

Example:

// 将浮点数四舍五入为整数
$number = round(3.14); // 3

// 将字符串转换为对象
$obj = (object) ["name" => "John"];

Practical case: database interaction

In the MySQL database, the values ​​in the result set are usually stored as strings. For proper data analysis, these values ​​need to be converted to the appropriate type. For example:

$query = "SELECT age FROM users";
$result = $mysqli->query($query);

while ($row = $result->fetch_assoc()) {
  // 将 age 列转换为整数
  $age = (int) $row['age'];
}

By following these guidelines, you can effectively perform PHP type conversions, solve various data conversion problems, and improve the readability and reliability of your code.

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