overview of php php basics datatypes arrays

Arrays
Strings and regular expressions
Basic PHP Syntax
CS380
1

Arrays
2
 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
CS380
$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

Array functions
3
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, processing elements

Array function example
4
 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

foreach loop
5
foreach ($array as $variableName) {
...
} PHP
CS380
$fellowship = array(“Frodo", “Sam", “Gandalf",
“Strider", “Gimli", “Legolas", “Boromir");
print “The fellowship of the ring members are: n";
for ($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

Multidimensional Arrays
6
<?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

Multidimensional Arrays (cont.)
7
<?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
CS380

String compare functions
8
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

String compare functions
examples
9
$offensive = array( offensive word1, offensive
word2);
$feedback = str_replace($offcolor, “%!@*”,
$feedback);
PHP
CS380
$test = “Hello World! n”;
print strpos($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

Regular expressions
10
[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
CS380

Printing HTML tags in PHP =
bad style
12
<?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?

PHP expression blocks
13
 PHP expression block: a small piece of PHP that
evaluates and embeds an expression's value into HTML
 <?= expression ?> is equivalent to:
<?= expression ?> PHP
CS380
<h2> The answer is <?= 6 * 7 ?> </h2>
PHP
The answer is 42
output
<?php print expression; ?>
PHP

Expression block example
14
<!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

Common errors: unclosed
braces, missing = sign
15
...
<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

Complex expression blocks
16
...
<body>
<?php
for ($i = 1; $i <= 3; $i++) {
?>
<h<?= $i ?>>This is a level <?= $i ?>
heading.</h<?= $i ?>>
<?php
}
?>
</body> PHP
CS380
This is a level 1 heading.
This is a level 2 heading.
This is a level 3 heading. output

Functions
Advanced PHP Syntax
17
CS380

Functions
18
function name(parameterName, ..., parameterName) {
statements;
} PHP
CS380
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

Default Parameter Values
19
function print_separated($str, $separator = ", ") {
if (strlen($str) > 0) {
print $str[0];
for ($i = 1; $i < strlen($str); $i++) {
print $separator . $str[$i];
}
}
} PHP
CS380
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

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
20

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.
CS380
21

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