For example, here's a quick dummy function that sums it up:
function dummy_func($optional)
{
if (!isset($optional)
{
$optional = "World!";
}
$output = "Hello " . $optional;
return $output;
}
However, if I run this, I get an E_WARNING for a missing argument. How can I set it up so it doesn't flag an error?
Optional arguments need to be given a default value. Instead of checking isset
on the argument, just give it the value you want it to have if not given:
function dummy_func($optional = "World!")
{
$output = "Hello " . $optional;
return $output;
}
See the page on Function arguments in the manual (particularly the Default argument values section).
You can do that by making $optional
argument take default value of "World!"
:
function dummy_func($optional="World!")
{
$output = "Hello " . $optional;
return $output;
}
Now when calling the function if you don't provide any argument, $optional
will take the default value but if you pass an argument, $optional
will take the value passed.
Example:
echo dummy_func(); // makes use of default value...prints Hello World!
echo dummy_func('foo!'); // makes use of argument passed...prints Hello foo!
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