Question

PHP is loosely Typed Language but could someone tell me, What is the default data type of any PHP variable? What is its implicit data Type?

Answer 1

The OP understands that PHP is a loosely typed language and therefore the type of any initialized variable is determined by the data it holds; so read that way, the question then becomes What is the type of an uninitialized variable? – the answer to which is null

PHP doesn’t generally allow you to declare variables without initializing them, there’s no direct equivalent to:

Dim SomeVar

Therefore the only way to see that “default” data type is to evaluate either a variable that hasn’t been set or a class member that holds no data.

1: A variable that hasn’t been set

echo $someVar === null ? "NULL" : "NOT NULL"; //outputs NULL (and triggers a Warning)

2: A declared class member that holds no data

class Test {
  public static $someVar;
}

var_dump(Test::$someVar); // outputs NULL

Therefore:

• the type of any initialized variable is determined by the data it holds

• the type of any uninitialized variable is null