PHP (Hypertext Preprocessor) is a popular open-source server-side scripting language

PHP Introduction
Dr.GINNE M JAMES
Assistant Professor
Department of Computer Science with Data Analytics
Sri Ramakrishna College of Arts and Science
Coimbatore - 641 006
Tamil Nadu, India
1

2
Arrays
Strings and regular expressions
Basic PHP Syntax

CS380
3
Arrays
 Append: use bracket notation without specifying an index
 Element type is not specified; can mix types
$name = array(); # create
$name = array(value0, value1, ..., valueN);
$name[index] # get element value
$name[index] = value; # set element value
$name[] = value; # append
PHP
$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

4
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

CS380
5
Array function example
 the array in PHP replaces many other collections in Java
 list, stack, queue, set, map, ...
$tas = array("MD", "BH", "KK", "HM", "JP");
for ($i = 0; $i < count($tas); $i++) {
$tas[$i] = strtolower($tas[$i]);
}
$morgan = array_shift($tas);
array_pop($tas);
array_push($tas, "ms");
array_reverse($tas);
sort($tas);
$best = array_slice($tas, 1, 2);
PHP

CS380
6
foreach loop
foreach ($array as $variableName) {
...
}
PHP
$fellowship = array(“Frodo", “Sam", “Gandalf",
“Strider", “Gimli", “Legolas", “Boromir");
print “The fellowship of the ring members are: n";
for ($i = 0; $i < count($fellowship); $i++) {
print "{$fellowship[$i]}n";
}
print “The fellowship of the ring members are: n";
foreach ($fellowship as $fellow) {
print "$fellown";
}
PHP

CS380
7
Multidimensional Arrays
<?php $AmazonProducts = array( array(“BOOK",
"Books", 50),
array("DVDs",
“Movies", 15),
array(“CDs", “Music",
20)
);
for ($row = 0; $row < 3; $row++) {
for ($column = 0; $column < 3; $column++) { ?>
 | <?= $AmazonProducts[$row]
[$column] ?>
<?php } ?>

<?php } ?>
PHP

CS380
8
Multidimensional Arrays (cont.)
<?php $AmazonProducts = array( array(“Code” =>“BOOK",
“Description” => "Books", “Price” => 50),
array(“Code” => "DVDs",
“Description” => “Movies", “Price” => 15),
array(“Code” => “CDs",
“Description” => “Music", “Price” => 20)
);
for ($row = 0; $row < 3; $row++) { ?>
 | <?= $AmazonProducts[$row][“Code”] ?> | <?=
$AmazonProducts[$row][“Description”] ?> | <?=
$AmazonProducts[$row][“Price”] ?>

<?php } ?>
PHP

9
String compare functions
Name Function
strcmp compareTo
strstr, strchr find string/char within a string
strpos find numerical position of string
str_replace, substr_replace replace string
 Comparison can be:
 Partial matches
 Others
 Variations with non case sensitive functions
 strcasecmp

CS380
10
String compare functions
examples
$offensive = array( offensive word1, offensive
word2);
$feedback = str_replace($offcolor, “%!@*”,
$feedback);
PHP
$test = “Hello World! n”;
print strpos($test, “o”);
print strpos($test, “o”, 5);
PHP
$toaddress = “feedback@example.com”;
if(strstr($feedback, “shop”)
$toaddress = “shop@example.com”;
else if(strstr($feedback, “delivery”)
$toaddress = “fulfillment@example.com”;
PHP

CS380
11
Regular expressions
[a-z]at #cat, rat, bat…
[aeiou]
[a-zA-Z]
[^a-z] #not a-z
[[:alnum:]]+ #at least one alphanumeric char
(very) *large #large, very very very large…
(very){1, 3} #counting “very” up to 3
^bob #bob at the beginning
com$ #com at the end
PHPRegExp
 Regular expression: a pattern in a piece of text
 PHP has:
 POSIX
 Perl regular expressions

13
Printing HTML tags in PHP = bad
style
<?php
print "<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML
1.1//EN"n";
print " "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
n";
print "<html xmlns="http://www.w3.org/1999/xhtml">n";
print " <head>n";
print " <title>Geneva's web page</title>n";
...
for ($i = 1; $i <= 10; $i++) {
print " I can count to $i! n";
}
?>
HTML
 best PHP style is to minimize print/echo statements in
embedded PHP code
 but without print, how do we insert dynamic content into the
page?

CS380
14
PHP expression blocks
 PHP expression block: a small piece of PHP that evaluates and
embeds an expression's value into HTML
 <?= expression ?> is equivalent to:
<?= expression ?>
PHP
<h2> The answer is <?= 6 * 7 ?> </h2>
PHP
The answer is 42
output
<?php print expression; ?>
PHP

15
Expression block example
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head><title>CSE 190 M: Embedded PHP</title></head>
<body>
<?php
for ($i = 99; $i >= 1; $i--) {
?>
 <?= $i ?> bottles of beer on the wall, 
<?= $i ?> bottles of beer. 
Take one down, pass it around, 
<?= $i - 1 ?> bottles of beer on the wall. 
<?php
}
?>
</body>
</html> PHP

CS380
16
Common errors: unclosed braces,
missing = sign
...
<body>
Watch how high I can count:
<?php
for ($i = 1; $i <= 10; $i++) {
?>
<? $i ?>

</body>
</html> PHP
 if you forget to close your braces, you'll see an error about
'unexpected $end'
 if you forget = in <?=, the expression does not produce any
output

CS380
17
Complex expression blocks
...
<body>
<?php
for ($i = 1; $i <= 3; $i++) {
?>
<h<?= $i ?>>This is a level <?= $i ?>
heading.</h<?= $i ?>>
<?php
}
?>
</body> PHP
This is a level 1 heading.
This is a level 2 heading.
This is a level 3 heading. output

18
CS380
Functions
Advanced PHP Syntax

CS380
19
Functions
function name(parameterName, ..., parameterName) {
statements;
} PHP
function quadratic($a, $b, $c) {
return -$b + sqrt($b * $b - 4 * $a * $c) / (2
* $a);
} PHP
 parameter types and return types are not written
 a function with no return statements implicitly returns NULL

CS380
20
Default Parameter Values
function print_separated($str, $separator = ", ") {
if (strlen($str) > 0) {
print $str[0];
for ($i = 1; $i < strlen($str); $i++) {
print $separator . $str[$i];
}
}
} PHP
print_separated("hello"); # h, e, l, l, o
print_separated("hello", "-"); # h-e-l-l-o
PHP
 if no value is passed, the default will be used

CS380
21
PHP Arrays Ex. 1
 Arrays allow you to assign multiple values to one variable. For
this PHP exercise, write an array variable of weather conditions
with the following values: rain, sunshine, clouds, hail, sleet, snow,
wind. Using the array variable for all the weather conditions,
echo the following statement to the browser:
We've seen all kinds of weather this month. At the beginning of the
month, we had snow and wind. Then came sunshine with a few
clouds and some rain. At least we didn't get any hail or sleet.
 Don't forget to include a title for your page, both in the header
and on the page itself.

CS380
22
PHP Arrays Ex. 2
 For this exercise, you will use a list of ten of the largest cities in
the world. (Please note, these are not the ten largest, just a
selection of ten from the largest cities.) Create an array with the
following values: Tokyo, Mexico City, New York City, Mumbai,
Seoul, Shanghai, Lagos, Buenos Aires, Cairo, London.
 Print these values to the browser separated by commas, using a
loop to iterate over the array. Sort the array, then print the
values to the browser in an unordered list, again using a loop.
 Add the following cities to the array: Los Angeles, Calcutta,
Osaka, Beijing. Sort the array again, and print it once more to
the browser in an unordered list.

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