Solution to PHP empty function error_PHP tutorial

When developing in PHP, when you use empty to check the result returned by a function, an error will be reported: Fatal error: Can't use function return value in write context

For example, the following code:

Copy the code The code is as follows:

echo empty( strlen('test'));

Go to the PHP manual and see the following text where the empty function is described:

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Note : empty() only variables checks as anything else will result in a parse error. In other words, the following will not work: empty(trim($name)).

Conclusion: empty() only Detecting variables, testing anything that is not a variable will result in a parsing error!

Therefore, we cannot use empty to directly detect the value returned by the function. The solution to the above example is as follows:

Copy the code The code is as follows:

$length = strlen('test');
echo empty($length);

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