Parsing the Boolean type of PHP data type (Boolean)

This is the simplest type. boolean expresses a truth value and can be TRUE or FALSE.

Syntax

To specify a Boolean value, use the keywords TRUE or FALSE. Both are not case sensitive.

Usually the boolean value returned by the operator will be passed to the control flow.

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}
// ...因为可以使用下面这种简单的方式：
if ($show_separators) {
   echo "
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}
?>

Convert to Boolean

To explicitly convert a value to boolean, use (bool) or (boolean) to cast. But in many cases, casting is not necessary because when an operator, function, or flow control structure requires a boolean parameter, the value is automatically converted.

See the identification of type conversion.

When converted to boolean, the following values ​​are considered FALSE:

• Boolean value FALSE itself

• Integer value 0 (zero)

• Floating point value 0.0 (zero)

• The empty string, and the string "0"

• An array that does not include any elements

• An object that does not include any member variables (only applicable to PHP 4.0)

• Special type NULL (including variables that have not been assigned a value)

• SimpleXML objects generated from XML documents without any tags

All All other values ​​are considered TRUE (including any resources).

Warning

-1, like other non-zero values ​​(positive or negative), is considered TRUE!

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