Are there any best practices for distinguishing between NULL and an empty string when using isset in PHP?

When using isset in PHP to check if a variable is set, it can be tricky to distinguish between NULL and an empty string, as isset considers both as not being set. To differentiate between the two, you can use the strict comparison operator (===) along with the empty function to check if a variable is explicitly set to an empty string. 

$variable = NULL;

if (isset($variable) && $variable !== '') {
    echo 'Variable is set and not an empty string.';
} elseif (isset($variable) && $variable === '') {
    echo 'Variable is set and is an empty string.';
} else {
    echo 'Variable is not set.';
}

Keywords

PHP isset NULL empty string best practices

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