PHP - Boolean


How can we use a boolean?

$foo = True;

How can we cast a variable to a boolean?

To explicitly convert a value to boolean, use the (bool) or (boolean) casts. However, in most cases the cast is unnecessary, since a value will be automatically converted if an operator, function or control structure requires a boolean argument.

What are considered as false?

  1. the boolean FALSE itself
  2. the integer 0 (zero)
  3. the float 0.0 (zero)
  4. the empty string, and the string "0"
  5. an array with zero elements
  6. an object with zero member variables (PHP 4 only)
  7. the special type NULL (including unset variables)
  8. SimpleXML objects created from empty tags

Every other value is considered TRUE (including any resource).

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