Course Notes:
Chapter Four:
Loops & Arrays.
Simple loop.
For loop
syntax:
for ( initialize a counter; conditional statement; increment a counter){ do this code; }
<html>
<head>
<title>
A simple For Loop
</title>
</head>
<body>
<h1>A simple for loop</h1>
<?php
for ($i = 0; $i < 10; $i++){
print "$i <br>\n";
} // end for loop
?>
</body>
</html>
Alternative way of dispaying with for loop
simpleFor2.php
<html>
<head>
<title>
For Loop
</title>
</head>
<body>
<h1>for loop</h1>
<?php
$brush_price = 5;
echo "<table border=\"1\" align=\"center\">";
echo "<tr><th>Quantity</th>";
echo "<th>Price</th></tr>";
for ( $counter = 10; $counter <= 100; $counter += 10)
{
echo "<tr><td>";
echo $counter;
echo "</td><td>";
echo $brush_price * $counter;
echo "</td></tr>";
} // end for loop
echo "</table>";
?>
</body>
</html>
**NOTE THE ECHO ECHO ECHO....
While loop
syntax
while(contition true)
{code to execute;
codition terminator code;}
while.php
<html>
<head>
<title>
A simple While Loop
</title>
</head>
<body>
<h1>A simple while loop</h1>
<?php
$i = 1;
while ($i <= 10){
print "$i <br>\n";
$i++;
} // end while
?>
PHP Arrays:
An array is a data structure that stores one or more values in a single variable. For experienced programmers it is important to note that PHP's arrays are actually maps (each key is mapped to a value).
A Numerically Indexed Array
If this is your first time seeing an array, then you may not quite understand the concept of an array. Imagine that you own a business and you want to store the names of all your employees in a PHP variable. How would you go about this?
It wouldn't make much sense to have to store each name in its own variable. Instead, it would be nice to store all the employee names inside of a single variable. This can be done, and we show you how below.
PHP Code:
$employee_array[0] = "Bob";
$employee_array[1] = "Sally";
$employee_array[2] = "Charlie";
$employee_array[3] = "Clare";
In the above example we made use of the key / value structure of an array. The keys were the numbers we specified in the array and the values were the names of the employees. Each key of an array represents a value that we can manipulate and reference. The general form for setting the key of an array equal to a value is:
$array[key] = value;
If we wanted to reference the values that we stored into our array, the following PHP code would get the job done.
PHP Code:
echo "Two of my employees are "
. $employee_array[0] . " & " . $employee_array[1];
echo "<br />Two more employees of mine are "
. $employee_array[2] . " & " . $employee_array[3];
Display:
Two of my employees are Bob & Sally
Two more employees of mine are Charlie & Clare
Arrays consisting solely of atomic entities are referred to as being single-dimensional. Multidimensional arrays consist of other arrays. For example, you could use a multidimensional array to store U.S. state information. Using PHP syntax, it might look like this:
$states = array ("Ohio" => array ("population" => "11,353,140", "capital"
=> "Columbus"),
"Nebraska" => array("population" => "1,711,263",
"capital" => "Omaha")
)
You could then reference Ohio’s population like so:
$states["Ohio"]["population"]
This would return the following value:
11,353,140
Basic Arrays basicArray.php
</body>
</html>
<html>
<head>
<title>
Basic Array
</title>
</head>
<body>
<h1>Basic Array</h1>
<?php
//simply assign values to array
$camelPop[1] = "Somalia";
$camelPop[2] = "Sudan";
$camelPop[3] = "Mauritania";
$camelPop[4] = "Pakistan";
$camelPop[5] = "India";
//output array values
print "<h3>Top Camel Populations in the World</h3>\n";
for ($i = 1; $i <= 5; $i++){
print "$i: $camelPop[$i]<br>\n";
} // end for loop
print "<i>Source: <a href = http://www.fao.org/ag/aga/glipha/index.jsp target=_blank> Food and Agriculture Organization of the United Nations</a></i>\n";
//use array function to load up array
$binary = array("000", "001", "010", "011");
print "<h3>Binary numbers</h3>\n";
for ($i = 0; $i < count($binary); $i++){
print "$i: $binary[$i]<br>\n";
} // end for loop
?>
</body>
</html>
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