Which array function checks if the specified key exists in the array?

Which of the following is not related to file

What is the name of the function to check that the variable type is an object?

The ______ keyword is used to indicate an incomplete class or method, which must be further extended and/or implemented in order to be used.

Which of the following responsible for generates the backtrace

Which of the following is not a boolean false

Which is NOT correct about PHP 7.1 variables?

Which can be used as a default value for parameters that are declared as iterable?

Output will be? $o = (object) array( var_dump(isset($o-> {'5'})); var_dump(key($o)); ?>

Find the output of the following PHP 7.1 code. var_dump(round(35/6)); ?>

Correct magical PHP constant that is used to determine the current line number of a file?