Cindra Onggo

The foreach Statement

onggo — Thu, 27 Nov 2008 03:00:23 +0000

The foreach statement is used to loop through arrays.

For every loop, the value of the current array element is assigned to $value (and the array pointer is moved by one) – so on the next loop, you’ll be looking at the next element.

Syntax

foreach (array as value)
{
    code to be executed;
}

Example

The following example demonstrates a loop that will print the values of the given array:


foreach ($arr as $value)
{
  echo "Value: " . $value . "
";
}
?>

No related posts.

Related posts brought to you by Yet Another Related Posts Plugin.

The do…while Statement

onggo — Thu, 27 Nov 2008 02:51:06 +0000

The do…while statement will execute a block of code at least once – it then will repeat the loop as long as a condition is true.

Syntax

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

Example

The following example will increment the value of i at least once, and it will continue incrementing the variable i as long as it has a value of less than 5:

";
  }
while ($i<5);
?>

No related posts.

Related posts brought to you by Yet Another Related Posts Plugin.

The while Statement

onggo — Tue, 18 Nov 2008 06:09:06 +0000

The while statement will execute a block of code if and as long as a condition is true.

Syntax

while (condition)
code to be executed;

Example

The following example demonstrates a loop that will continue to run as long as the variable i is less than, or equal to 5. i will increase by 1 each time the loop runs:

";
  $i++;
  }
?>

No related posts.

Related posts brought to you by Yet Another Related Posts Plugin.

Looping

onggo — Tue, 18 Nov 2008 06:06:23 +0000

Very often when you write code, you want the same block of code to run a number of times. You can use looping statements in your code to perform this.

In PHP we have the following looping statements:

* while – loops through a block of code if and as long as a specified condition is true
* do…while – loops through a block of code once, and then repeats the loop as long as a special condition is true
* for – loops through a block of code a specified number of times
* foreach – loops through a block of code for each element in an array

No related posts.

Related posts brought to you by Yet Another Related Posts Plugin.

Multidimensional Arrays

onggo — Tue, 18 Nov 2008 06:04:32 +0000

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

In this example we create a multidimensional array, with automatically assigned ID keys:

$families = array
(
  "Griffin"=>array
  (
  "Peter",
  "Lois",
  "Megan"
  ),
  "Quagmire"=>array
  (
  "Glenn"
  ),
  "Brown"=>array
  (
  "Cleveland",
  "Loretta",
  "Junior"
  )
);

The array above would look like this if written to the output:

Array
(
[Griffin] => Array
  (
  [0] => Peter
  [1] => Lois
  [2] => Megan
  )
[Quagmire] => Array
  (
  [0] => Glenn
  )
[Brown] => Array
  (
  [0] => Cleveland
  [1] => Loretta
  [2] => Junior
  )
)

Example 2

Lets try displaying a single value from the array above:

echo "Is " . $families['Griffin'][2] .
" a part of the Griffin family?";

The code above will output:

Is Megan a part of the Griffin family?

No related posts.

Related posts brought to you by Yet Another Related Posts Plugin.

Associative Arrays

onggo — Tue, 18 Nov 2008 06:02:12 +0000

An associative array, each ID key is associated with a value.

When storing data about specific named values, a numerical array is not always the best way to do it.

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

Example 1

In this example we use an array to assign ages to the different persons:

$ages = array("Peter"=>32, "Quagmire"=>30, "Joe"=>34);

Example 2

This example is the same as example 1, but shows a different way of creating the array:

$ages['Peter'] = "32";
$ages['Quagmire'] = "30";
$ages['Joe'] = "34";

The ID keys can be used in a script:


$ages['Peter'] = "32";
$ages['Quagmire'] = "30";
$ages['Joe'] = "34";
echo "Peter is " . $ages['Peter'] . " years old.";
?>

The code above will output:

Peter is 32 years old.

No related posts.

Related posts brought to you by Yet Another Related Posts Plugin.

Numeric Arrays

onggo — Tue, 18 Nov 2008 05:56:18 +0000

A numeric array stores each element with a numeric ID key.

There are different ways to create a numeric array.

Example 1

In this example the ID key is automatically assigned:

$names = array("Peter","Quagmire","Joe");

Example 2

In this example we assign the ID key manually:

$names[0] = "Peter";
$names[1] = "Quagmire";
$names[2] = "Joe";

The ID keys can be used in a script:


$names[0] = "Peter";
$names[1] = "Quagmire";
$names[2] = "Joe";
echo $names[1] . " and " . $names[2] .
" are ". $names[0] . "'s neighbors";
?>

The code above will output:

Quagmire and Joe are Peter's neighbors

No related posts.

Related posts brought to you by Yet Another Related Posts Plugin.

The Switch Statement

onggo — Tue, 18 Nov 2008 05:49:35 +0000

If you want to select one of many blocks of code to be executed, use the Switch statement.

The switch statement is used to avoid long blocks of if..elseif..else code.

Syntax

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

Example

This is how it works:

A single expression (most often a variable) is evaluated once
The value of the expression is compared with the values for each case in the structure
If there is a match, the code associated with that case is executed
After a code is executed, break is used to stop the code from running into the next case
The default statement is used if none of the cases are true

No related posts.

Related posts brought to you by Yet Another Related Posts Plugin.

The ElseIf Statement

onggo — Tue, 18 Nov 2008 05:33:53 +0000

If you want to execute some code if one of several conditions are true use the elseif statement

Syntax

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;

Example

The following example will output “Have a nice weekend!” if the current day is Friday, and “Have a nice Sunday!” if the current day is Sunday. Otherwise it will output “Have a nice day!”:

No related posts.

Related posts brought to you by Yet Another Related Posts Plugin.

The If…Else Statement

onggo — Tue, 18 Nov 2008 05:28:34 +0000

If you want to execute some code if a condition is true and another code if a condition is false, use the if….else statement.

Syntax

if (condition)
  code to be executed if condition is true;
else
  code to be executed if condition is false;

Example

The following example will output “Have a nice weekend!” if the current day is Friday, otherwise it will output “Have a nice day!”:

If more than one line should be executed if a condition is true/false, the lines should be enclosed within curly braces:

";
  echo "Have a nice weekend!";
  echo "See you on Monday!";
  }
?>

No related posts.

Related posts brought to you by Yet Another Related Posts Plugin.