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57 Cards in this Set

  • Front
  • Back
SYNTAX:

basic variable
$var_name = value;

NOTE:
***must have $ sign in front.
***line must end with semi-colon;
***variable does not need to be declared before using it.
NAMING RULES for variables:
* A variable name must start with a letter or an underscore "_"

* A variable name can only contain alpha-numeric characters and underscores (a-z, A-Z, 0-9, and _ )

* A variable name should not contain spaces. If a variable name is more than one word, it should be separated with an underscore ($my_string), or with capitalization ($myString)
There is only one "string operator" in PHP
(.) use the period put strings values together

EXAMPLE:
<?php
$txt1="Hello World!";
$txt2="What a nice day!";
echo $txt1 . " " . $txt2;
?>
SYNTAX:

return the length of a string.
the strlen() function

EXAMPLE:
<?php
echo strlen("Hello world!");
?>
SYNTAX:

find the position of a match
the strpos() function

EXAMPLE:
<?php
echo strpos("Hello world!","world");
?>
SYNTAX:

The if...else statement
if (condition)

code to be executed if condition is true;

else

code to be executed if condition is false;

EXAMPLE:
<html>
<body>

<?php
$d=date("D");
if ($d=="Fri")
echo "Have a nice weekend!";
else
echo "Have a nice day!";
?>

</body>
</html>
SYNTAX:

The if...elseif...else statement
if (condition)

code
to be executed if condition is true;

elseif (condition)

code to be executed if condition is true;

else

code to be executed if condition is false;
SYNTAX:

The switch statement
switch (n)
{
case label1:
code to be executed if n=label1;
break;
case label2:
code to be executed if n=label2;
break;
default:
code to be executed if n is different from both label1 and label2;
}
SYNTAX:

numeric array
$cars=array("Saab","Volvo","BMW","Toyota");

OR

$cars[0]="Saab";
$cars[1]="Volvo";
$cars[2]="BMW";
$cars[3]="Toyota";
EXAMPLE:

calling a "numeric array"
<?php
$cars[0]="Saab";
$cars[1]="Volvo";
$cars[2]="BMW";
$cars[3]="Toyota";
echo $cars[0] . " and " . $cars[1] . " are Swedish cars.";
?>
What is a "numeric array"?
A numeric array stores each array element with a numeric index.
What is an "associative array"?
*** An associative array, each ID key is associated with a value.

*** With associative arrays we can use the values as keys and assign values to them.
EXAMPLE:

associative array
<?php
$ages['Peter'] = "32";
$ages['Quagmire'] = "30";
$ages['Joe'] = "34";

echo "Peter is " . $ages['Peter'] . " years old.";
?>
Definition:

What is a multidimensional array.
In a multidimensional array, each element in the main array can also be an array. And each element in the sub-array can be an array, and so on.
EXAMPLE:

create a multidimensional array, with automatically assigned ID keys:
$families = array
(
"Griffin"=>array
(
"Peter",
"Lois",
"Megan"
),
"Quagmire"=>array
(
"Glenn"
),
"Brown"=>array
(
"Cleveland",
"Loretta",
"Junior"
)
);
SYNTAX:

a while loop
while (condition)
{
code to be executed;
}
EXAMPLE:

while loop
<html>
<body>

<?php
$i=1;
while($i<=5)
{
echo "The number is " . $i . "<br />";
$i++;
}
?>

</body>
</html>
SYNTAX:

do...while
do
{
code to be executed;
}
while (condition);

NOTE: the do..while will execute at least once.
SYNTAX:

for loop
for (init; condition; increment)
{
code to be executed;
}
SYNTAX:

foreach loop
foreach ($array as $value)
{
code to be executed;
}
EXAMPLE:

foreach loop
<html>
<body>

<?php
$x=array("one","two","three");
foreach ($x as $value)
{
echo $value . "<br />";
}
?>

</body>
</html>
SYNTAX:

create a PHP function
function functionName()
{
code to be executed;
}

PHP function guidelines:

*** Give the function a name that reflects what the function does

*** The function name can start with a letter or underscore (not a number)
FUNCTION:

WHICH function takes all the content in a specified file and includes it in the current file?
include() function
....takes all the content in a specified file and includes it in the current file.

NOTE:
If an error occurs, the include() function generates a warning, but the script will continue execution.

EXAMPLE:
<html>
<body>

<?php include("header.php"); ?>
<h1>Welcome to my home page!</h1>
<p>Some text.</p>

</body>
</html>
FUNCTION:

WHICH function is similar to include() ?

AND what is the difference
require()

DIFFERENCE: the require() function generates a "fatal error" and the script will stop.
FUNCTION:

HOW do you open a file in PHP?
fopen()

EXAMPLE:
<html>
<body>

<?php
$file=fopen("welcome.txt","r");
?>

</body>
</html>
List some "modes" of
fopen()
Modes Description
r Read only. Starts at the beginning of the file

r+ Read/Write. Starts at the beginning of the file

w Write only. Opens and clears the contents of file; or creates a new file if it doesn't exist

w+ Read/Write. Opens and clears the contents of file; or creates a new file if it doesn't exist

a Append. Opens and writes to the end of the file or creates a new file if it doesn't exist

a+ Read/Append. Preserves file content by writing to the end of the file

x Write only. Creates a new file. Returns FALSE and an error if file already exists

x+ Read/Write. Creates a new file. Returns FALSE and an error if file already exists
give an example of an fopen message...if it is unable to open a file.
EXAMPLE:

<html>
<body>

<?php
$file=fopen("welcome.txt","r") or exit("Unable to open file!");
?>

</body>
</html>
FUNCTION:

How to close an opened file.
fclose($file);

EXAMPLE:
<?php
$file = fopen("test.txt","r");

//some code to be executed

fclose($file);
?>
FUNCTION:

How to check the end-of-file
feof($file)

NOTE:
You cannot read from files opened in w, a, and x mode!

EXAMPLE:
if (feof($file)) echo "End of file";
FUNCTION:

how to read a file line-by-line.
fgets()
...is used to read a single line from a file.

EXAMPLE:
<?php
$file = fopen("welcome.txt", "r") or exit("Unable to open file!");
//Output a line of the file until the end is reached
while(!feof($file))
{
echo fgets($file). "<br />";
}
fclose($file);
?>
FUNCTION:

how to read a file character-by-character.
fgetc()
... is used to read a single character from a file.

EXAMPLE:
<?php
$file=fopen("welcome.txt","r") or exit("Unable to open file!");
while (!feof($file))
{
echo fgetc($file);
}
fclose($file);
?>
SYNTAX:

create a "constant"
define("constantname","constantvalue");

NOTE:
constants are like variables, except that they are not changed.
SYNTAX:

calling a "constant"
EXAMPLE:
echo contstantName;

NOTE:
*** constants do not use $ sign.
*** constants cannot use quotes.
PHP predefined variables (superglobals):

...that contains any variables provided to a script through the GET method.
$_GET
PHP predefined variables (superglobals):

...that contains any variables provided to a script through the POST method.
$_POST
PHP predefined variables (superglobals):

...that contains any variables provided to a script through a cookie.
$_COOKIE
PHP predefined variables (superglobals):

...that contains any variables provided to a script through file uploads.
$_FILES
PHP predefined variables (superglobals):

...that contains information such as headers, file paths, and script locations.
$_SERVER
PHP predefined variables (superglobals):

...that any variables provided to a script as part of the server environment.
$_ENV
PHP predefined variables (superglobals):

...that contains any variables provided to a script via GET, POST, or COOKIE input mechanisms.
$_REQUEST
PHP predefined variables (superglobals):

...that contains any variables that are currently registered in a session.
$_SESSION
PHP Variable Testing (data types):

checks if variable is null
.is_null($variable);
PHP Variable Testing (data types):

checks if variable is a integer
.is_int($variable);
PHP Variable Testing (data types):

checks if variable is a string
.is_string($variable);
PHP Variable Testing (data types):

checks if variable is a floating point (or double)
.is_double($variable);
PHP Variable Testing (data types):

checks if variable is boolean
.is_bool($variable);
PHP Variable Testing (data types):

checks if variable is an array
.is_array($variable);
PHP Variable Testing (data types):

checks if variable is a number
.is_numeric($variable);
PHP Variable Testing (data types):

checks if variable is a resource
.is_resource($variable);
PHP Variable Testing (data types):

test if variable is null
.is_array($testing);
PHP VARIABLES:

How to set the type of variable.
settype($variabletochange, 'new type');
PHP VARIABLES:

Changing Type by Casting. What is this?
EXAMPLE:
$newvar = (integer) $originalvar

EXPLANATION:
creates a copy of original (does not affect the original)
PHP "predefined constants":

...what will return the name of the file that the PHP engine is currently reading.
__FILE__
PHP "predefined constants":

...that will return the current line number of the file.
__LINE__
PHP "predefined constants":

...what will give the version of PHP is interpreting the script
PHP_VERSION
Four Methods:
How to make system calls using PHP
1. backticks ` `
2. system("command; command ");
3. exec()
4. pasthru()
what line can be added at the top of a php script to display errors
init_set("display_errors", "On");

WARNING:
script debugging only. NOT good for public facing pages