PHP

Question 1

What is a PHP script?

Answer 1

a file composed of HTML tags and PHP code inserted between<?php and ?>tags

Question 2

What is a PHP Engine?

Answer 2

It compiles the requested PHP script and executes the code

Question 3

What is contained in the php.ini file?

Answer 3

Configuration settings for PHP files

Question 4

How is an echo statement used by a PHP script?

Answer 4

It produces output that is sent to the browser via HTTP response.

Question 5

What setting in php.ini files controls error message generation?

Answer 5

error_reporting

Question 6

What setting in php.ini files determines if error messages are sent to the browser??

Answer 6

display_errors

Question 7

What are the four types of error messages in PHP?

Answer 7

• Parse Error: Syntax error when code is compiled
• Fatal Error: Runtime Error that halts execution
• Warning: Runtime error that doesn’t halt execution
• Notice: Runtime message of possible logic error

Question 8

How are variables declared in PHP?

Answer 8

By initializing the variable.

Question 9

What are the three rules for naming variables in PHP?

Answer 9

• Names must start with a $ symbol
• Can be any combination of letters, digits, or underscores
• May not start with a digit following the $

Question 10

What is the difference between variable names, and functions / keyword names in PHP?

Answer 10

Variables are case sensitive, functions and keywords are not

Question 11

How are PHP Constants different to variables?

Answer 11

• Constants cannot be changed
• Constants do not use $ in the name
• They are usually CAPITALIZED

Question 12

How are PHP constants defined?

Answer 12

With the define(name, value) function or the const keyword

Question 13

What is ‘variable interpolation’?

Answer 13

When the PHP engine substitutes the value of a variable for the variable name inside of a double-quoted string

Question 14

What is the difference between double quoted and Single quoted strings in PHP?

Answer 14

• Single quotation strings disable variable interpolation.
• The only escape sequences in single quotation strings are // and /’

Question 15

What is the PHP String concatenation operator?

Answer 15

A period

Question 16

How does PHP handle strings encountered in an arithmetic expression?

Answer 16

• The string converted into an int
• Strings with “E” or “e” are evaluated as scientific notation.
• A string with leading digits can be converted into a number, but PHP generates a warning.
• Attempting arithmetic with a string that has no leading digits causes a fatal error.

Question 17

In addition to the standard compound assignment operators,what additional operators are present in PHP?

Answer 17

• %= Mod By
• .= Concatenation

Question 18

What are the additional comparison operators in PHP vs Java?

Answer 18

• <> (inequality)
• === (identical: values and types must be the same)
• !== (Not Identical)
• <=> (Spaceship: acts as java equals() returning an int)

Question 19

Does a PHP switch statement compare with == or ===?

Answer 19

==

Question 20

What is a PHP array?

Answer 20

An ordered collection of key/value pairs.
Keys must be integers or strings, but values can be any datatype

Question 21

What are the two types of PHP arrays?

Answer 21

• Indexed Array: Array with integer keys, similar to java array.
• Associative Array: String keys

Question 22

What is the syntax of a foreach loop in PHP?

Answer 22

foreach($array as $value) {//body}

Question 23

In a PHP associative array, what is the syntax for value assignment?

Answer 23

“key” => “value”

Question 24

What are the 3 method pairs to sort PHP arrays?

Answer 24

• sort() / rsort(): sort indexed arrays in ascending / descending order
• asort() / arsort(): sort associative arrays based on values in ascending / descending order.
• ksort() / krsort(): sort associative arrays based on keys in ascending / descending order.

Question 25

How are functions declared in PHP?

Answer 25

With the 'function' keyword. Ex: function helloWorld() {//body}

Question 26

How is case used in PHP function names?

Answer 26

Functions are case insensitive.

Question 27

How are global variables accessed in PHP functions?

Answer 27

With the 'global' keyword. Ex: global $variable;

Question 28

Are PHP function arguments pass-by-value or pass-by-reference?

Answer 28

Pass-by-value

Question 29

How are PHP function arguments made to be pass-by-reference?

Answer 29

With the ampersand character. Ex: &$argVariable.

Question 30

How are PHP method arguments given default values.

Answer 30

With the "=" operator. Ex: method($variable = "defaul value")

Question 31

What is a variable length argument list in PHP?

Answer 31

A list of function arguments that can change in number.

Question 32

How is a variable length argument list declared in PHP?

Answer 32

With the '...' token. Ex: ...$args

Question 33

What do PHP classes contain?

Answer 33

- Properties (variables defined in a class) - Methods (functions defined in a class).

Question 34

How are PHP class objects created?

Answer 34

With the "new" keyword.

Question 35

How are PHP object properties / methods accessed?

Answer 35

With the object operator "->". Ex: $object->method()

Question 36

How are a PHP object's properties accessed within its methods?

Answer 36

With the "$this" variable and the object operator “->”. Ex: $this->property

Question 37

What is the function name of a PHP class constructor?

Answer 37

__construct

Question 38

What is the function name of a PHP class destructor?

Answer 38

__destruct

Question 39

How does a PHP class specify a parent class to inherit properties / methods?

Answer 39

With the "extends" keyword.

Question 40

What are the access modifiers of PHP class properties / methods?

Answer 40

- public: the default when no modifier is stated - protected: only accessible by class or children. - private: only accessible by defining class.

Question 41

How are static properties / methods accessed outside of PHP objects?

Answer 41

With the scope resolution operator "::". Ex: className::$staticVariable.

Question 42

How are static properties / methods accessed within PHP objects?

Answer 42

With the "self" keyword and the scope resolution operator "::". Ex: self::staticMethod()

Question 43

Which PHP function can parse a file into an array of strings?

Answer 43

preg_split

Question 44

Which PHP function takes a string and parses it into an array?

Answer 44

explode(delimiter, string)

Question 45

What PHP function takes an array and combines it together into a string?

Answer 45

implode(delimiter, array)

Question 46

What PHP function reads a file and returns the contents as a string?

Answer 46

file_get_contents(file_path)