A brief analysis of PHP data type conversion _php Tutorial

PHP does not need (or does not support) explicit type definitions in variable definitions; The variable type is determined by the context in which the variable is used. That is, if you assign a string value to the variable Var,var it becomes a string. If you assign an integer value to Var, it becomes an integer.

An example of automatic type conversion for PHP is the plus sign "+". If any one operand is a floating-point number, all operands are treated as floating-point numbers, and the result is a floating-point number. Otherwise the operand is interpreted as an integer, and the result is an integer. Note that this does not change the type of the operands themselves; it only changes how the operands are evaluated and the type of the expression itself.

Type casting
The allowable casts are:

• (int), (integer)-Convert to Integer (integer)
• (bool), (Boolean)-Convert to Boolean (Boolean)
• (float), (double), (real)-convert to floating-point (float)
• (string)-Convert to String (string)
• (binary)-Convert to binary string (string) (PHP 6)
• (array)-Convert to Arrays (array)
• (object)-Convert to Object (objects)
• (unset)-Convert to NULL (PHP 5)
The (binary) conversion will precede the result with the prefix ' B ', PHP 5.2.1 new.

Note that spaces and tabs are allowed inside the parentheses

Converts string literals and variables to binary strings (string):

Copy the Code code as follows:
$binary = (binary) $string;
$binary = B "binary string";
?>

If you want to change the type of a variable, see Settype ();

settype-setting the type of a variable

BOOL Settype (mixed $var, string $type)
Set the type of the variable var to type.

The possible values for type are:

• "Boolean" (or "bool", starting from PHP 4.2.0)
• "Integer" (or "int", starting from PHP 4.2.0)
• "Float" (only available after PHP 4.2.0, for "double" used in older versions is now disabled)
• "String"
• "Array"
• "Object"
• "Null" (from PHP 4.2.0)
Returns TRUE on success, or FALSE on failure.

Intval (), Floatval (), Strval (), these three functions can also be converted

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