- var_dump: documentation ( source)
<?php
$test = array();
$test['eval_none'] = '';
$test['eval_zero'] = 0;
$test['eval_null'] = null;
$test['eval_false'] = false;
$test['eval_true'] = true;
if (isset($test['eval_nonexixtent'])) var_dump('Noneexistent is set.');
if (!empty($test['eval_nonexixtent'])) var_dump('Noneexistent is not empty.');
if (isset($test['eval_none'])) var_dump('None is set.');
if (!empty($test['eval_none'])) var_dump('None is not empty.');
if (isset($test['eval_zero'])) var_dump('Zero is set.');
if (!empty($test['eval_zero'])) var_dump('Zero is not empty.');
if (isset($test['eval_null'])) var_dump('NULL is set.');
if (!empty($test['eval_null'])) var_dump('NULL is not empty.');
if (isset($test['eval_false'])) var_dump('False is set.');
if (!empty($test['eval_false'])) var_dump('False is not empty.');
if (isset($test['eval_true'])) var_dump('True is set.');
if (!empty($test['eval_true'])) var_dump('True is not empty.');