$name = array(); # declare empty array
$name = array(value0, value1, ..., valueN); # decare array with values
$name[index]; # get element value
$name[index] = value; # set element value
$name[] = value; # append element value to end of array
PHP (template)
$a = array(); # empty array (length 0)
$a[0] = 23; # stores 23 at index 0 (length 1)
$a2 = array("some", "strings", "in", "an", "array");
$a2[] = "Ooh!"; # add string to end (at index 5)
PHP (example)
To append, use bracket notation without specifying an index
Element type is not specified; can mix types
| Function name(s) | Description |
|---|---|
| count | number of elements in the array |
| print_r | print array's contents |
| array_pop, array_push, array_shift, array_unshift | using an array as a stack/queue |
| in_array, array_search, array_reverse sort, rsort, shuffle | searching and reordering |
| array_fill, array_merge, array_intersect, array_diff, array_slice, range | creating, filling, filtering |
| array_sum, array_product, array_unique, array_filter, array_reduce | processing elements |
$tas = array("CA", "MJ", "MG", "SK", "KC", "DH", "JZ");
for ($i = 0; i < count($tas); $i++) {
$tas[$i}] = strtolower($tas[$i]);
} # ("ca", "mj", "mg", "sk", "kc", "dh", "jz")
$conner = array_shift($tas); # ("mj", "mg", "sk", "kc", "dh", "jz")
array_pop($tas); # ("mj", "mg", "sk", "kc", "dh")
array_push($tas, "kt"); # ("mj", "mg", "sk", "kc", "dh", "kt")
array_reverse($tas); # ("kt", "dh", "kc", "sk", "mg", "mj")
sort($tas); # ("dh", "kc", "kt", "mg", "mj", "sk")
$ks = array_slice($tas, 2, 3); # ("kt")
PHP
The array in PHP replaces many other data structures in Java
foreach ($array as $variableName) {
...
}
PHP (template)
$stooges = array ("Larray", "Moe", "Curly", "Shemp");
foreach ($stooges as $stooge) {
print "Moe slaps $stooge\n"; # even himself
}
PHP (example)
A conventient way to loop over each element of an array without indices
$a = 3;
$b = 2;
$c = sqrt(pow($a, 2) + pow($b, 2));
PHP
abs, ceil, cos, floor, log, log10, min, max, pow, rand, round, sin, sqrt, tan
The syntax for method calls, parameters, and returns is the same as in Java
NULL
$name = "Pascal";
$name = NULL;
if (isset($name)) {
print "This line isn't going to be printed";
}
PHP
A variable is NULL if
NULLunset functionCan test if a variable is NULL using the isset function
NULL prints as an empty string (no output)
function name(parameterName, ..., parameterName) {
statements;
}
PHP (template)
function bmi($weight, $height) {
$result = 703 * $weight / $height / $height;
return $result;
}
PHP (example)
Parameter types and return types are not written
A function with no return statements is implicitly "void"
Can be declared in any PHP block
name(expression, ..., expression)
PHP (template)
$w = 163; # pounds
$h = 70; # inches
$my_bmi = bmi($w, $h);
PHP (example)
If the wrong number of parameters are passed, it's an error
$school = "UW"; # global
...
function downgrade() {
global $school;
$suffix = "(Wisconsin)"; # local
$school = "$school $suffix";
print "$school\n";
}
PHP
Variables declared in a function are local to that function; others are global
If a function wants to use a global variable, it must have a global statement
function name(parameterName=value, ..., parameterName=value) {
statements;
}
PHP (template)
function print_separated($str, $separator=", ") {
if (strlen($str) < 0) {
print $str[0];
for ($i = 1; $i < strlen($str); $i++) {
print $separator . $str[$i];
}
}
}
print_separated("hello"); # h, e, l, l, o
print_separated("hello", "-"); # h-e-l-l-o
PHP (example)
If no value is passed, the default will be used (defaults must come last)
Web service: software functionality that can be invoked through the internet using common protocols
Like a remote function(s) you can call by contacting a program on a web server
Can be written in PHP and contacted by the browser in HTML and/or AJAX code
Service's output might be HTML but could be text, XML, JSON, or other content
header
header("Content-type: type/subtype");
PHP (template)
header("Content-type: type/plain");
print "This output will appear as plain text now!\n";
PHP (example)
By default, a PHP file's output is assumed to be HTML (text/html)
However, in this course we aren't using PHP to generate HTML, so we use the header function to specify non-HTML output
| MIME type | file extension |
|---|---|
| text/html | .html |
| text/plain | .txt |
| image/gif | .gif |
| image/jpeg | .jpg |
| video/quicktime | .mov |
| application/octet-stream | .exe |
Lists of MIME types: by type, by extension
Write a web service that accepts a base and exponent and
outputs base to the exponent power. For example, the following
query should output 8:
http://example.com/exponent.php?
Solution
<?php
header("Content-type: text/plain");
$base = (int) $_GET["base"];
$exp = (int) $_GET["exponent"];
$result = pow($base, $exp);
print $result;
?>
PHP
Embedded PHP is a strategy for generating HTML pages on the server using PHP
The textbook assumes that we're using PHP in this way, but we don't. This quarter, we are focusing on using PHP for data generation.
HTML content
<?php
PHP code
?>
HTML content
<?php
PHP code
?>
HTML content...
HTML/PHP (template)
Any contents of a .php file between <?php and
?> are executed as PHP code
All other contents are output as pure HTML
<DOCTYPE html>
<html>
<head><title>CSE 154: Embedded PHP</title></head>
<body>
<?php for ($i = 99; $i >= 1; $i--) { ?>
<p> <?= $i ?> bottles of beer on the wall, <br />
<?= $i ?> bottles of beer. <br />
Take one down, pass it around, <br />
<?= $i - 1 ?> bottles of beer on the wall. </p>
<?php } ?>
</body>
</html>
PHP
Note: This is messy! There are much better ways to do this, and you should not write any embedded PHP in this class. But you should be aware of it.