class 3intro to databases arrays sending values to a script manually for and while loops

Class 3Intro to Databases

Arrays

Sending Values to a Script Manually

For and While Loops


Arrays

There are 2 main types of arrays in PHP

•Numerical Arrays

•Indexed Arrays

We’re going to look at how to create and access these variables.

In PHP there are also several “built-in” arrays. These are called superglobal arrays. We’re going to look at 2 commonly used in form processing.

$_POST

$_GET


Numerical Arrays

An numeric array is a list of items, for example:

$artists=(“Alice Neel”, “Robert Rauschenberg “, “Kiki Smith”, “Dan Flavin”);

To create an array

$artists=array();

To put values in an array


Will add all at once

or

$artists[4]= “Giotto”;

Will add at a specific location

or

$artists[]= “Giotto”;

Will add at end


Numerical Arrays


To access values

To access values in numerical arrays, we use the index number

$this_artist= $artists[0];

echo "My favorite artist is ".$this_artist; //prints Alice Neel

Download arrays_numeric.zip

Change arrays_numeric.php to print out an artists name

Note that arrays start at ZERO


Numerical Arrays

To add values$artists[4]= “Giotto”;

Will add at a specific location

or$artists[]= “Giotto”;Will add at end

Either will give us

$artists=(“Alice Neel”, “Robert Rauschenberg “, “Kiki Smith”, “Dan Flavin”, “Giotto”);

In arrays_numeric.php

Add an artist’s name to the end of the array

And print it out

$this_artist= $artists[4];echo "<br> or maybe it's ".$this_artist; //prints Giotto


Getting the number of elements in an array

/ /get the count of an array$total_artists=count($artists);echo "<p>There are ".$total_artists." artists in my list";

In arrays_numeric.php print out the number of elements in your array


While Loop


The While Loop//using the WHILE loopprint("<p><b>Using the WHILE loop</b>");

$i=0;while($i<$total_artists){

print("<br> $artists[$i]");$i++;

}

In arrays_numeric.php use the WHILE loop to print out all the values

Note that we are keeping track of 3 variables here

$artist is the array holding the artists names

$total_artist holds the number of items in our array

$i is used as a counter in the WHILE loop.We initialize it at 0We set the condition that it must be less than $total artistAnd we increment 1 each time it goes through the loop


For Loop


The FOR Loop// print them all out, using the FOR loopprint("<p><b>Using the FOR loop</b>");

for($i=0; $i<$total_artists; $i++){print("<br> $artists[$i]");

}

In arrays_numeric.php use the FOR loop to print out all the values

Note that we are keeping track of 3 variables here

$artist is the array holding the artists names

$total_artist holds the number of items in our array

$i is used as a counter in the FOR loop.We initialize it at 0We set the condition that it must be less than $total artistAnd we increment 1 each time it goes through the loop


ForEach Loop


The FOREACH Loop// print them all out, using the FOREACH loopprint("<p><b>Using the FOREACH loop</b>");

foreach($artists as $value){print("<br> $value");

}

In arrays_numeric.php use the FOREACH loop to print out all the values


ForEach Loop


To print out all values// printing another wayecho "<p>Another way to print the contents";

// print each artist as $valueforeach($artists as $value){

print("<br> $value");}

In arrays_numeric.php use the FOREACH loop to print out all the values

Here we can access each element of a for loop using FOREACH


Indexed Arrays

An indexed array is a list of items. Each item is made up of a key/value pair.

The key is how you access the value.

$artists=array('oil paint'=>'Alice Neel', 'mixed media'=>'Robert Rauschenberg', 'bronze'=>'Kiki Smith', 'fluorescent lights'=>'Dan Flavin');


Indexed Arrays

To create an array$artists=array();

To put values in an array

$artists=array('oil paint'=>'Alice Neel', 'mixed media'=>'Robert

Rauschenberg', 'bronze'=>'Kiki Smith', 'fluorescent

lights'=>'Dan Flavin');

or

$artists[‘fresco’]= “Giotto”;


Indexed Arrays

$artists=array('oil paint'=>'Alice Neel', 'mixed media'=>'Robert Rauschenberg', 'bronze'=>'Kiki Smith', 'fluorescent lights'=>'Dan Flavin');

To access values

To access values in indexed arrays, we use the key

$this_artist= $artists[‘oil paint’];

echo "My favorite oil painter is ".$this_artist; //prints Alice Neel

Download arrays_indexed.zip

Change arrays_indexed.php to print out an artists name

Note that arays start at ZERO


Numerical Arrays

To add values$artists[‘fresco’]= “Giotto”;

Will add a value with this key

Gives us$artists=array('oil paint'=>'Alice Neel', 'mixed media'=>'Robert Rauschenberg', 'bronze'=>'Kiki Smith ', 'fluorescent lights'=>'Dan Flavin ', ‘fresco'=>'Dan Flavin ');

In arrays_indexed.php

Add an artist’s name the array

And print it out

$artists[‘fresco’]= “Giotto”; echo "<br>My favorite fresco painter is".$this_artist;

//prints Giotto


ForEach Loop

$artists=array('oil paint'=>'Alice Neel', 'mixed media'=>'Robert Rauschenberg', 'bronze'=>'Kiki Smith ', 'fluorescent lights'=>'Dan Flavin ', ‘fresco'=>'Dan Flavin ');

The FOREACH Loop// print them all out, using the FOREACH loopecho "<p><b>In original order</b>";

foreach($artists as $key=>$value){print("<br> <i> $key </i> $value");

}

In arrays_indexed.php use the FOREACH loop to print out all the keys and values


Sorting by Value


ASORT// print them all out, sorted by valueecho "<p><b>Sorted by artist name</b>";asort($artists);


}

In arrays_indexed.php use the ASORT to print out all the keys and values


Sorting by Key


KSORT // print them all out, sorted by key echo "<p><b>Sorted by medium</b>";ksort($artists);


}

In arrays_indexed.php use the ASORT to print out all the keys and values



Here we’re going to look at how to send hidden variables in a form.



Download and unzip cl_3_manual.zip

HTML (calculator.html)

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/2000/REC-xhtml1-20000126/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"><head>

<meta http-equiv="content-type" content="text/html; charset=iso-8859-1" /><title>Cost Calculator</title>

</head><body>



<form action="handle_calculator.php?source=calculator.html" method="post">

<select name="quantity"><option value="">Select a quantity:</option><option value="1">1</option><option value="2">2</option><option value="3">3</option><option value="4">4</option><option value="5">5</option><option value="6">6</option>

</select>

<div align="left"><input type="submit" name="submit" value="Total!" /></div>

<input type="hidden" name="price" value="19.95" /><input type="hidden" name="taxrate" value=".05" />

</form>

</body></html>



HTML

<form action="handle_calculator.php?source=calculator.html" method="post">

Here we are sending both POST and GET variables

When a variable is sent in a url string it is a GET variable

When variables are sent through a form they can be either GET or POST variables, depending on the form METHOD

2 IMPORTANT ARRAYS

POST variables can be accessed using the superglobal $_POST

GET variables can be accessed using the superglobal $_GET



PHP (handle_calculator.php)<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN“ "http://www.w3.org/TR/2000/REC-xhtml1-20000126/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"><head>

<meta http-equiv="content-type" content="text/html; charset=iso-8859-1" /><title>Cost Calculator</title>

</head><body><?php# Script 2.8 - handle_calculator.php

if (isset($_GET['source'])) {

if ($_GET['source'] == 'calculator.html') { // Are they coming from the right page?

if (is_numeric($_POST['quantity'])) { // Is the quantity a number?

// Make the calculations and print the results.$total = ($_POST['quantity'] * $_POST['price']) * ($_POST['taxrate'] + 1);$total = number_format ($total, 2);echo "You are purchasing <b>{$_POST['quantity']}</b> widget(s) at a cost of

<b>\${$_POST['price']}</b> each. With tax, the total comes to <b>\$$total</b>.\n";

} else { // Quantity is not a number.echo '<p><b>Please enter a valid quantity to purchase!</b></p>';

}

} else { // The source is not right.echo '<p><b>You have accessed this page inappropriately!</b></p>';

}

} else { // The source is not set.echo '<p><b>You have accessed this page inappropriately!</b></p>';

}

?></body></html>



Upload calculator.html and handle_calculator.php

Change the price & tax rate

class 3intro to databases arrays sending values to a script manually for and while loops

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