My ZCE studies didn’t expose me to these edge cases, well except for the first one.
If you use == watch out for these and related:
<?php echo ((0 == 'hello') ? 'true' : 'false').PHP_EOL; //true echo ((0 == '1hello') ? 'true' : 'false').PHP_EOL; //false echo (('0' == '0e0') ? 'true' : 'false').PHP_EOL; //true echo (('0' == '0e0e') ? 'true' : 'false').PHP_EOL; //false echo (('0' == '0ee') ? 'true' : 'false').PHP_EOL; //false echo ((0 == '0x0') ? 'true' : 'false').PHP_EOL; //true echo ((0 == '0x0x') ? 'true' : 'false').PHP_EOL; //true echo ((0 == '0x0b') ? 'true' : 'false').PHP_EOL; //false ?> |
Whoa, we don’t want any of these to return true, what’s a developer to do?
Strict comparisons with ===
<?php echo ((0 === 'hello') ? 'true' : 'false').PHP_EOL; //false echo ((0 === '1hello') ? 'true' : 'false').PHP_EOL; //false echo (('0' === '0e0') ? 'true' : 'false').PHP_EOL; //false echo (('0' === '0e0e') ? 'true' : 'false').PHP_EOL; //false echo (('0' === '0ee') ? 'true' : 'false').PHP_EOL; //false echo ((0 === '0x0') ? 'true' : 'false').PHP_EOL; //false echo ((0 === '0x0x') ? 'true' : 'false').PHP_EOL; //false echo ((0 === '0x0b') ? 'true' : 'false').PHP_EOL; //false ?> |
Much better.
Learn more at http://php.net/manual/en/types.comparisons.php