Menu
It seems like my code works to check for null if I do
if ($tx)
or
if (isset($tx))
why would I do the second one when it's harder to write?
574
Definition and Usage The isset() function checks whether a variable is set, which means that it has to be declared and is not NULL. This function returns true if the variable exists and is not NULL, otherwise it returns false.
The isset() function is a built-in function of PHP, which is used to determine that a variable is set or not. If a variable is considered set, means the variable is declared and has a different value from the NULL. In short, it checks that the variable is declared and not null.
The equivalent of isset($var) for a function return value is func() === null . isset basically does a !== null comparison, without throwing an error if the tested variable does not exist.
isset() is best for radios/checkboxes. Use empty() for strings/integer inputs. when a variable contains a value, using isset() will always be true. you set the variable yourself, so it's not a problem.
if ($tx)
This code will evaluate to false for any of the following conditions:
unset($tx); // not set, will also produce E_WARNING
$tx = null;
$tx = 0;
$tx = '0';
$tx = false;
$tx = array();
The code below will only evaluate to false under the following conditions:
if (isset($tx))
// False under following conditions:
unset($tx); // not set, no warning produced
$tx = null;
For some people, typing is very important. However, PHP by design is very flexible with variable types. That is why the Variable Handling Functions have been created.
102
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
