PHP Boolean Type (Boolean)

This is the simplest type. Boolean expresses the truth value, which can be TRUE or FALSE.

Grammar

To specify a Boolean value, use the keyword TRUE or FALSE. Two are not case-sensitive.

<?php$foo = True; Assign the value TRUE to $foo?> The Boolean result returned by the usual operator is passed to the control flow. <?php//= = is an operator that detects whether two variables are equal and returns a Boolean if ($action = = "Show_version") {   echo "The version is 1.23";} This is not necessary ... if ($show _separators = = TRUE) {   echo "
Convert to a Boolean value

To explicitly convert a value to a Boolean, use either (BOOL) or (Boolean) to cast. However, there are many cases where casting is not required because the value is automatically converted when an operator, function, or process control structure requires a Boolean parameter.

See discriminant for type conversions.

When converted to Boolean, the following values are considered FALSE:

The Boolean value FALSE itself

Integer value 0 (0)

Floating-point value 0.0 (0)

An empty string, and the string "0"

An array that does not include any elements

Objects that do not include any member variables (PHP 4.0 only applies)

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

SimpleXML object generated from an XML document without any tags (tags)

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

Warning

-1 and other non-0 values (either positive or negative) are considered to be true!

<?phpvar_dump ((BOOL) "");        BOOL (FALSE) Var_dump ((bool) 1);         BOOL (True) Var_dump ((BOOL)-2);        BOOL (True) Var_dump ((bool) "foo");     BOOL (True) Var_dump ((bool) 2.3e5);     BOOL (True) Var_dump ((BOOL) array (12)); BOOL (True) Var_dump ((bool) array ());   BOOL (FALSE) Var_dump ((bool) "false");   BOOL (TRUE)?>
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