PHP Data Type Check

php-data-type-check.php

<?php

// data to be tested
$data = [
	null,
	false,
	true,
	0,
	1,
	'',
	'hello',
	array(),
	array(1, 2, 3),
	new \stdClass,
	function () {
		return true;
	}
];

foreach ($data as $value) {
	// format name for value being tested
	if (is_string($value)) {
		$valueName = '"' . $value . '"';
	} elseif (is_bool($value)) {
		$valueName = ($value) ? 'true' : 'false';
	} elseif (is_null($value)) {
		$valueName = 'NULL';
	} elseif (is_array($value)) {
		$valueName = 'Array(' . count($value) . ')';
	} elseif (is_object($value)) {
		if ($value instanceof \Closure) {
			$valueName = 'Closure';
		} else {
			$valueName = 'Object';
		}
	} else {
		$valueName = $value;
	}

	// run the tests
	if ($value == false) {
		echo $valueName . ' (typeof ' . strtolower(gettype($value)) . ') is false (loosely typed)' . PHP_EOL;
	} else {
		echo $valueName . ' (typeof ' . strtolower(gettype($value)) . ') is not false (loosely typed)' . PHP_EOL;
	}
	if ($value === false) {
		echo $valueName . ' (typeof ' . strtolower(gettype($value)) . ') is false (strictly typed)' . PHP_EOL;
	} else {
		echo $valueName . ' (typeof ' . strtolower(gettype($value)) . ') is not false (strictly typed)' . PHP_EOL;
	}
	if ($value == true) {
		echo $valueName . ' (typeof ' . strtolower(gettype($value)) . ') is true (loosely typed)' . PHP_EOL;
	} else {
		echo $valueName . ' (typeof ' . strtolower(gettype($value)) . ') is not true (loosely typed)' . PHP_EOL;
	}
	if ($value === true) {
		echo $valueName . ' (typeof ' . strtolower(gettype($value)) . ') is true (strictly typed)' . PHP_EOL;
	} else {
		echo $valueName . ' (typeof ' . strtolower(gettype($value)) . ') is not true (strictly typed)' . PHP_EOL;
	}
	if (empty($value)) {
		echo $valueName . ' (typeof ' . strtolower(gettype($value)) . ') is empty' . PHP_EOL;
	} else {
		echo $valueName . ' (typeof ' . strtolower(gettype($value)) . ') is not empty' . PHP_EOL;
	}
	if ($value == null) {
		echo $valueName . ' (typeof ' . strtolower(gettype($value)) . ') is null (loosely typed)' . PHP_EOL;
	} else {
		echo $valueName . ' (typeof ' . strtolower(gettype($value)) . ') is not null (loosely typed)' . PHP_EOL;
	}
	if (is_null($value)) {
		echo $valueName . ' (typeof ' . strtolower(gettype($value)) . ') is null (strictly typed)' . PHP_EOL;
	} else {
		echo $valueName . ' (typeof ' . strtolower(gettype($value)) . ') is not null (strictly typed)' . PHP_EOL;
	}
	if (isset($value)) {
		echo $valueName . ' (typeof ' . strtolower(gettype($value)) . ') is set' . PHP_EOL;
	} else {
		echo $valueName . ' (typeof ' . strtolower(gettype($value)) . ') is not set' . PHP_EOL;
	}

	// line separation between tests
	echo PHP_EOL;
}