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1. 1. What is a function parameter?

   What is a function parameter?

   A database table The value printed by echo A PHP file path only A named input declared by the function
   Hint

   Focus on the responsibility of the language feature rather than memorizing punctuation.

2. 2. What is a function argument?

   What is a function argument?

   The function name A CSS declaration A value supplied when the function is called A required PHP comment
   Hint

   Focus on the responsibility of the language feature rather than memorizing punctuation.

3. 3. What does a default parameter value allow?

   What does a default parameter value allow?

   The value becomes a global constant The function runs only once PHP ignores the parameter The caller may omit that argument
   Hint

   Focus on the responsibility of the language feature rather than memorizing punctuation.

4. 4. What is the practical difference between return and echo?

   What is the practical difference between return and echo?

   return gives a value to the caller; echo writes output return works only with strings They are always identical echo ends the function; return prints HTML
   Hint

   Focus on the responsibility of the language feature rather than memorizing punctuation.

5. 5. By default, can a function directly use a variable declared outside it?

   By default, can a function directly use a variable declared outside it?

   Yes, every variable is global Only in WordPress admin Only when the value is an array No, not unless it is passed in or explicitly brought into scope
   Hint

   Focus on the responsibility of the language feature rather than memorizing punctuation.

6. 6. What does the global keyword do inside a function?

   What does the global keyword do inside a function?

   Loads another file Makes the function public on the internet Links a local name to a variable in the global scope Creates a PHP constant
   Hint

   Focus on the responsibility of the language feature rather than memorizing punctuation.

7. 7. What does isset( $value ) check?

   What does isset( $value ) check?

   That the value is a string That the variable exists and is not null That the value is true only That the variable is globally scoped
   Hint

   Focus on the responsibility of the language feature rather than memorizing punctuation.

8. 8. When does empty( $value ) return true?

   When does empty( $value ) return true?

   When the value is undefined or considered empty or false-like Only for an empty array Only after unset() Only when it is null
   Hint

   Focus on the responsibility of the language feature rather than memorizing punctuation.

9. 9. What does count( $items ) return for an array?

   What does count( $items ) return for an array?

   A sorted copy The sum of numeric values The last array key The number of elements
   Hint

   Focus on the responsibility of the language feature rather than memorizing punctuation.

10. 10. What does in_array( $needle, $haystack, true ) do?

    What does in_array( $needle, $haystack, true ) do?

    Checks only array keys Adds the value to the array Removes duplicate values Checks for a value using strict type comparison
    Hint

    Focus on the responsibility of the language feature rather than memorizing punctuation.

11. 11. How does array_key_exists() differ from isset() for an array key containing null?

    How does array_key_exists() differ from isset() for an array key containing null?

    There is no difference array_key_exists returns true while isset returns false array_key_exists removes the key isset throws an exception
    Hint

    Focus on the responsibility of the language feature rather than memorizing punctuation.

12. 12. What is array_map() commonly used for?

    What is array_map() commonly used for?

    Convert every value to HTML automatically Create an array by applying a callback to each value Write an array to the database Sort an array by keys only
    Hint

    Focus on the responsibility of the language feature rather than memorizing punctuation.

13. 13. What is array_filter() commonly used for?

    What is array_filter() commonly used for?

    Merge PHP files Catch exceptions Rename every key Keep values that satisfy a callback
    Hint

    Focus on the responsibility of the language feature rather than memorizing punctuation.

14. 14. What does array_merge() do?

    What does array_merge() do?

    Checks strict equality Stops a loop Prints an array Combines values from arrays into a new array
    Hint

    Focus on the responsibility of the language feature rather than memorizing punctuation.

15. 15. Why use asort() instead of sort() for an associative array?

    Why use asort() instead of sort() for an associative array?

    asort returns a new array without changes sort cannot handle strings asort sorts only descending asort preserves key associations
    Hint

    Focus on the responsibility of the language feature rather than memorizing punctuation.

16. 16. What is a PHP callback?

    What is a PHP callback?

    A database rollback A PHP opening tag An HTTP redirect A callable value passed so other code can invoke it later
    Hint

    Focus on the responsibility of the language feature rather than memorizing punctuation.

17. 17. What is an anonymous function?

    What is an anonymous function?

    A function value declared without a normal function name A missing function A private class only A function with no parameters
    Hint

    Focus on the responsibility of the language feature rather than memorizing punctuation.

18. 18. What is the purpose of try and catch?

    What is the purpose of try and catch?

    Handle exceptions thrown while running a block of code Validate HTML Define an array key Repeat a loop
    Hint

    Focus on the responsibility of the language feature rather than memorizing punctuation.

19. 19. What does error_log() help a developer do?

    What does error_log() help a developer do?

    Create a WordPress user Display every error to visitors Repair PHP syntax Write diagnostic information to the configured error log
    Hint

    Focus on the responsibility of the language feature rather than memorizing punctuation.

20. 20. Why add parameter and return type declarations?

    Why add parameter and return type declarations?

    They document and enforce expected value types They create database indexes They encrypt values They replace all validation
    Hint

    Focus on the responsibility of the language feature rather than memorizing punctuation.