Semis Lecture 1 Flashcards by Mel Que

___ is a server scripting language, and a powerful tool for making dynamic and interactive Web pages.

PHP

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PHP is a ___, and a powerful tool for making dynamic and interactive Web pages.

server scripting language

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PHP is a widely-used, free, and efficient alternative to competitors such as ___.

Microsoft’s ASP

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sample php code block

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PHP is an acronym for…

“PHP: Hypertext Preprocessor”

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PHP is a widely-used, …

open source scripting language

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___ are executed on the server

PHP scripts

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PHP is free to ___

download and use

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What is a PHP File? PHP files can contain… (5)

text, HTML, CSS, JavaScript, and PHP code

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___ are executed on the server, and the result is returned to the browser
as plain HTML

PHP code

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PHP files have extension…

“.php”

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What Can PHP Do?
* PHP can generate ___
* PHP can ___ on the server
* PHP can collect ___
* PHP can ___ cookies
* PHP can ___ in your database
* PHP can be used to ___
* PHP can ___

dynamic page content;
create, open, read, write, delete, and close files;
form data;
send and receive;
add, delete, modify data;
control user-access;
encrypt data

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With PHP you are not limited to ___. You can output (a), (b), and even (c). You can also output any text, such as (d) and (e).

output HTML; (a) images, (b) PDF files, (c) Flash movies, (d) XHTML, (e) XML

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Why PHP?
* PHP runs on ___ (Windows, Linux, Unix, Mac OS X, etc.)

various platforms

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Why PHP?
* PHP is compatible with ___ (Apache, IIS, etc.)

almost all servers used today

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Why PHP?
* PHP supports a ___

wide range of databases

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Why PHP?
* PHP is ___. Download it from the official PHP resource: www.php.net

free

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Why PHP?
* PHP is ___ and ___ on the server side

easy to learn; runs efficiently

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To start using PHP, you can:
* Find a ___ with PHP and MySQL support
* Install a ___ on your own PC, and then install PHP and MySQL

web host; web server

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Use a Web Host with PHP Support
* If your server has activated support for PHP…
* Just create some ___, place them in your web directory, and the server will automatically parse them for you.
* You do not need to compile anything or install any extra tools.
* Because PHP is free, most ___ offer PHP support.
* Set Up PHP on Your Own PC

you do not need to do anything;
.php files;
web hosts

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However, if your server does not support PHP, you must:
* install a (a)
* install (b)
* install a (c), such as MySQL

(a) web server;
(b) PHP;
(c) database

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Basic PHP Syntax
* A ___ can be placed anywhere in the document.
* A PHP script starts with ___ and ends with ___

PHP script; <?php & ?>

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sample of basic php syntax

<?php
// PHP code goes
here ?>

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Example

<html>
<body>
<h1>My first PHP page</h1>

</body>
</html>

PHP statements end with a ___

semicolon (;)

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A ___ in PHP code is a line that is not read/executed as part of the program. Its only purpose is to be ___ who is looking at the code.

comment; read by someone

Comments can be used to: * Let others...

understand what you are doing

Comments can be used to: * Most programmers have experienced coming back to their own work a year or two later and having to re-figure out what they did. Comments can remind you of what you were thinking when you wrote the code

Remind yourself of what you did

php code snippet with comments example

Example

Example "; echo "Hello World!
"; EcHo "Hello World!
"; ?> does all those echos work?

yes

In the example below, only the first statement will display the value of the $color variable (this is because $color, $COLOR, and $coLOR are treated as three different variables): Example "; echo "My house is " . $COLOR . "
"; echo "My boat is " . $coLOR . "
"; ?>

when it comes to variables, php is case-sensitive

Data Types: Variables can store data of different types, and different data types can do different things. PHP supports the following data types: (8)

* String * Integer * Float (floating point numbers - also called double) * Boolean * Array * Object * NULL * Resource

A ___ is a sequence of characters, like "Hello world!".

string

A ___ can be any text inside quotes. You can use single or double quotes:

string

String Functions * Get The Length of a String * The ___ function returns the length of a string.

PHP strlen()

* The example below returns the length of the string "Hello world!" Example

OUPUT: 12

Count The Number of Words in a String The ___ function counts the number of words in a string: Example

PHP str_word_count(); OUPUT: 2

Reverse a String * The ___ function reverses a string: Example

PHP strrev(); OUTPUT: !dlrow olleH

Search For a Specific Text Within a String * The ___ function searches for a specific text within a string. * If a match is found, the function ___ of the first match. If no match is found, it will return ___. * The example below searches for the text "world" in the string "Hello world!": Example

PHP strpos(); returns the character position; FALSE; OUPUT: 6

Replace Text Within a String * The ___ function replaces some characters with some other characters in a string. * The example below replaces the text "world" with "Dolly": Example

PHP str_replace(); OUPUT: Hello Dolly!

PHP Integer: An ___ is a non-decimal number between -2,147,483,648 and 2,147,483,647.

integer data type

Rules for integers: * An integer must have (a) * An integer must not have a (b) * An integer can be (c) * Integers can be specified in three formats: (d, 3)

a - at least one digit b - decimal point c - either positive or negative d - decimal (10-based), hexadecimal (16-based - prefixed with 0x) or octal (8-based - prefixed with 0)

* In the following example $x is an integer. The ___ function returns the data type and value: Example

PHP var_dump(); OUTPUT: int(5985)

A ___ (floating point number) is a number with a decimal point or a number in exponential form.

float

In the following example $x is a float. The ___ function returns the data type and value: Example

PHP var_dump() ; OUTPUT: float(10.365)

A ___ represents two possible states: TRUE or FALSE. $x = true; $y = false;

Boolean

___ are often used in conditional testing.

Booleans

An ___ stores multiple values in one single variable

array

An ___ is a special variable, which can hold more than one value at a time.

array

An ___ can hold many values under a single name, and you can access the values by referring to an ___.

array; index number

Array Example

Create an Array in PHP * In PHP, the ___ function is used to create an array

array();

In PHP, there are three types of arrays:

* Indexed arrays * Associative arrays * Multidimensional arrays

Arrays with a numeric index

Indexed arrays

Arrays with named keys

Associative arrays

Arrays containing one or more arrays

Multidimensional arrays

___ are "containers" for storing information.

Variables

Creating (Declaring) PHP Variables: In PHP, a variable starts with the ___ sign, followed by the ___

$ ; name of the variable

Example of variable declaration "; echo $x; echo "
"; echo $y; ?>

Output: Hello world! 5 10.5

Note: When you assign a text value to a variable, put ___ around the value.

quotes

Note: Unlike other programming languages, PHP has ___. It is created the moment you first assign a value to it.

no command for declaring a variable

Rules for PHP variables:

A variable can have a short name (like x and y) or a more descriptive name (age, carname, total_volume). * A variable starts with the $ sign, followed by the name of the variable * A variable name must start with a letter or the underscore character * A variable name cannot start with a number * A variable name can only contain alpha-numeric characters and underscores (Az, 0-9, and _ ) * Variable names are case-sensitive ($age and $AGE are two different variables)

Output Variables * The ___ is often used to output data to the screen

PHP echo statement

In PHP, variables can be declared ___ in the script.

anywhere

The ___ is the part of the script where the variable can be referenced/used.

scope of a variable

PHP has three different variable scopes:

* local * global * static

A variable declared outside a function has a ___ and can only be accessed outside a function:

GLOBAL SCOPE

A variable declared within a function has a ___ and can only be accessed within that function:

LOCAL SCOPE

The ___ is used to access a global variable from within a function.

global keyword

To create a global variable, use the keyword: ___ before the variables (inside the function):

"global"

Normally, when a function is completed/executed, all of its variables are ___.

deleted

Sometimes we want a local variable NOT to be deleted.

To do this, use the keyword: "static " when you first declare the variable:

In PHP there are two basic ways to get output:

echo and print.

echo and print are more or less the same. They are both used to ___ to the screen.

output data

___ has no return value while ___ has a return value of 1 so it can be used in expressions.

echo; print

___ can take multiple parameters (although such usage is rare) while ___ can take one argument.

echo; print

which is marginally faster between echo and print?

echo

The echo statement can be used ___ parentheses:

with or without; echo or echo()

The print statement can be used ___ parentheses:

with or without; print or print()

An ___ is a data type which stores data and information on how to process that data.

object

* In PHP, an object must be ___. * First we must declare a ___. For this, we use the ___. A ___ is a structure that can contain properties and methods:

explicitly declared; class of object; class keyword; class

___ is a special data type which can have only one value: NULL.

Null

A variable of data type ___ is a variable that has no value assigned to it.

NULL

If a variable is created without a value, it is automatically assigned a value of ___.

NULL

Variables can also be emptied by setting the value to ___:

NULL

___ are like variables except that once they are defined they cannot be changed or undefined.

Constants

A ___ is an identifier (name) for a simple value. The value cannot be changed during the script.

constant

A ___ starts with a letter or underscore (no $ sign before the constant name).

valid constant name

Unlike variables, constants are ___ across the entire script.

automatically global

To create a constant, use the ___ function.

define()

define(name, value, case-insensitive)

Parameters: * name: Specifies the name of the constant * value: Specifies the value of the constant * case-insensitive: Specifies whether the constant name should be case-insensitive. Default is false

False or True: Constants are Global

True

___ are automatically global and can be used across the entire script.

Constants

___ are used to perform operations on variables and values.

Operators

PHP divides the operators in the following groups:

* Arithmetic operators * Assignment operators * Comparison operators * Increment/Decrement operators * Logical operators * String operators * Array operators

The ___ are used with numeric values to perform common arithmetical operations, such as addition, subtraction, multiplication etc.

PHP arithmetic operators

The ___ are used with numeric values to write a value to a variable.

PHP assignment operators

The basic assignment operator in PHP is ___. It means that the left operand gets set to the value of the assignment expression on the right

"="

The ___ are used to combine conditional statements.

PHP logical operators

PHP has two operators that are specially designed for strings

concatenation and concatenations assignment

The ___ are used to compare arrays.

PHP array operators