CSE 190M Web Programming

Lecture 8: Advanced PHP; File I/O

Reading: 5.4

Except where otherwise noted, the contents of this document are Copyright 2012 Marty Stepp, Jessica Miller, Victoria Kirst and Roy McElmurry IV. All rights reserved. Any redistribution, reproduction, transmission, or storage of part or all of the contents in any form is prohibited without the author's expressed written permission.

Valid HTML5 Valid CSS

5.4: Advanced PHP Syntax


$name = array();                         # create
$name = array(value0, value1, ..., valueN);

$name[index]                              # get element value
$name[index] = value;                      # set element value
$name[] = value;                          # append
$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)

Array functions

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 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

Array function example

$tas = array("MD", "BH", "KK", "HM", "JP");
for ($i = 0; $i < count($tas); $i++) {
	$tas[$i] = strtolower($tas[$i]);
}                                 # ("md", "bh", "kk", "hm", "jp")
$morgan = array_shift($tas);      # ("bh", "kk", "hm", "jp")
array_pop($tas);                  # ("bh", "kk", "hm")
array_push($tas, "ms");           # ("bh", "kk", "hm", "ms")
array_reverse($tas);              # ("ms", "hm", "kk", "bh")
sort($tas);                       # ("bh", "hm", "kk", "ms")
$best = array_slice($tas, 1, 2);  # ("hm", "kk")

The foreach loop

foreach ($array as $variableName) {
$stooges = array("Larry", "Moe", "Curly", "Shemp");
for ($i = 0; $i < count($stooges); $i++) {
	print "Moe slaps {$stooges[$i]}\n";
foreach ($stooges as $stooge) {
	print "Moe slaps $stooge\n";  # even himself!

Exercise: Beer Blog Nav Links

  • Use PHP arrays to reduce the redundancy in the Beer Blog navigational links.

Splitting/joining strings

$array = explode(delimiter, string);
$string = implode(delimiter, array);
$s  = "CSE 190 M";
$a  = explode(" ", $s);     # ("CSE", "190", "M")
$s2 = implode("...", $a);   # "CSE...190...M"

Example with explode

contents of input file names.txt
Martin D Stepp
Jessica K Miller
Victoria R Kirst
foreach (file("names.txt") as $name) {
	$tokens = explode(" ", $name);
	<p> author: <?= $tokens[2] ?>, <?= $tokens[0] ?> </p>

author: Stepp, Marty

author: Miller, Jessica

author: Kirst, Victoria

Exercise: Beer Blog Welcome Banner

  • Use PHP string functions to reduce the redundancy in the Beer Blog vertical welcome banner.


function name(parameterName, ..., parameterName) {
function bmi($weight, $height) {
	$result = 703 * $weight / $height / $height;
	return $result;

Calling functions

name(expression, ..., expression);
$w = 163;  # pounds
$h = 70;   # inches
$my_bmi = bmi($w, $h);

Variable scope: global and local vars

$school = "UW";                   # global

function downgrade() {
	global $school;
	$suffix = "(Wisconsin)";        # local

	$school = "$school $suffix";
	print "$school\n";

Default parameter values

function name(parameterName = value, ..., parameterName = value) {
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


$name = "Victoria";
$name = NULL;
if (isset($name)) {
	print "This line isn't going to be reached.\n";

6.1: Parameterized Pages

Query strings and parameters



Query parameters: $_GET

$user_name = $_GET["username"];
$id_number = (int) $_GET["id"];
$eats_meat = FALSE;
if (isset($_GET["meat"])) {
	$eats_meat = TRUE;

Example: Exponents

$base = $_GET["base"];
$exp = $_GET["exponent"];
$result = pow($base, $exp);
print "$base ^ $exp = $result";
3 ^ 4 = 81

Example: Print all parameters

<?php foreach ($_GET as $param => $value) { ?>
	<p>Parameter <?= $param ?> has value <?= $value ?></p>
<?php } ?>

Parameter name has value Marty Stepp

Parameter sid has value 1234567

Exercise: Beer Blog Song Verses

  • Use query parameters to enable us to have a variable number of verses in our Beer Blog anthem.
  • Use query parameters to enable us to have any drink in the Beer Blog anthem.

5.4: PHP File Input

PHP file I/O functions

function name(s) category
file, file_get_contents,
reading/writing entire files
basename, file_exists, filesize,
fileperms, filemtime, is_dir,
is_readable, is_writable, disk_free_space
asking for information
copy, rename, unlink, chmod,
chgrp, chown, mkdir, rmdir
manipulating files and directories
glob, scandir reading directories

Reading/writing files

contents of foo.txt file("foo.txt") file_get_contents("foo.txt")
how r u?

I'm fine
	"Hello\n",     # 0
	"how r u?\n",  # 1
	"\n",          # 2
	"I'm fine\n"   # 3
how r u?\n      # a single
\n              # string
I'm fine\n"

Exercise: Beer Blog Chapters & News

  • Use PHP file IO to reducte the redundancy in the Chapters section of the Beer Blog.
  • Use PHP file IO and functions to factor out the news section of the Beer Blog into a text file.
    • Make a function to format the news entries rather than inject them directly.

The file function

# display lines of file as a bulleted list
$lines = file("todolist.txt");
foreach ($lines as $line) {        # for ($i = 0; $i < count($lines); $i++)
	print $line;

Unpacking an array: list

list($var1, ..., $varN) = array;
contents of input file personal.txt
Marty Stepp
(206) 685 2181
list($name, $phone, $ssn) = file("personal.txt");
list($area_code, $prefix, $suffix) = explode(" ", $phone);

Reading directories

function description
glob returns an array of all file names that match a given pattern
(returns a file path and name, such as "foo/bar/myfile.txt")
scandir returns an array of all file names in a given directory
(returns just the file names, such as "myfile.txt")

glob example

# reverse all poems in the poetry directory
$poems = glob("poetry/poem*.dat");
foreach ($poems as $poemfile) {
	$text = file_get_contents($poemfile);
	file_put_contents($poemfile, strrev($text));
	print "I just reversed " . basename($poemfile) . "\n";

scandir example

	<?php foreach (scandir("taxes/old") as $filename) { ?>
		<li>I found a file: <?= $filename ?></li>
	<?php } ?>
  • .
  • ..
  • 2007_w2.pdf
  • 2006_1099.doc

Reading/writing an entire file

# reverse a file
$text = file_get_contents("poem.txt");
$text = strrev($text);
file_put_contents("poem.txt", $text);

Appending to a file

# add a line to a file
$new_text = "P.S. ILY, GTG TTYL!~";
file_put_contents("poem.txt", $new_text, FILE_APPEND);
old contents new contents
Roses are red,
Violets are blue.
All my base,
Are belong to you.
Roses are red,
Violets are blue.
All my base,
Are belong to you.