FooLab

PHP Workshop #1First Programming Experience

FooLabWho are you?

• Have you ever written PHP before?

• Have you ever written computer code before?

• Have you ever seen computer code?

• Ask for the name of your neighbor on each side.

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FooLabAnna Filina

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• PHP Quebec - user group, organizer.

• ConFoo - non for profit Web conference, organizer.

• FooLab Inc. - IT consulting, vice-president.

• I write code.

• I train people.

FooLabProgramming

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Input username

and password

Find username

Password matches?

Open account page

Display error message

Yes No

Describing procedures

FooLabFunctions

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pi 3.141592 ...

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Y-m-d date 2012-04-26

One step in the whole program

FooLabInteractive Shell

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• We can see result of PHP code as we type it.

• Open your console. Type phpsh

• After each line of code, press enter to execute it.

FooLabFunctions

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php> echo pi();

php> echo max(26,58);

php> echo max (26, 58);

php> echo date("Y-m-d");

FooLabInterpreter

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• I like like

php> echo echo;

• I like the word “like”

php> echo "echo";

FooLabData Types

• Integer, can’t confuse with commands or functions:

php> echo 33;

• String, use quotes:

php> echo "Programming is cool";

• There are more types, but that’s for later.

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FooLabVariables

• "Programming is cool"

• "Design is cool"

• "Video editing is cool"

php> $hobby = "Design";php> echo $hobby;php> echo "$hobby is cool";

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FooLab

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hobby

Design• Use the $ sign to refer

to the bin’s name.

• Use the = sign to put content in the bin.

$hobby = "Design"

FooLab

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hobby

Design• No sign is needed to get

the bin’s content out.

• A variable is where we put a value.

echo $hobby

FooLabWriting Code in Files

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• It’s easier to write multiple lines of code in a file.

• Open your text editor.

• Open the file /var/www/php1/script.php

FooLab

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• Quit the interactive shell by typing:

php> q

• Now you can run your file using:

$ php /var/www/php1/script.php

• Repeat the previous command by pressing the up arrow.

• Every time we edit our file, we’ll test the code.

FooLab

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• The file currently contains the following text:

<?php$hobby = "Design";echo "$hobby is cool";?>

• The file ends in empty lines. Don’t delete them.

FooLabMovie Price

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• Movie costs 12$

• Popcorn costs 8$

• Popcorn can be shared between two people.

FooLab

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• What happens with popcorn when we have an odd number of people?

ceil(3 / 2);

FooLabProcedure

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Set number of people

(variable)

Get number of popcorns required

Popcorns * 8

Tickets * 12Display sum

Calculate total movie cost based on number of people

FooLabPractice!

• Write a script that, given any number of people, calculates the total price for movie and popcorn.

• Set number of people (variable)

• Get number of popcorns required

• Popcorns * 8

• Tickets * 12

• Display sum

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FooLabAnswer

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<?php$people = 3;echo ceil($people / 2) * 8 + $people * 12;?>

FooLab

FunctionsUnderstanding Them and Writing Your Own

FooLab

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• Accept parameters

• Perform steps

• Return result

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FooLabCreate and Call a Function

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• Wrap code in a function:

function movie_price($people) { $total = ceil($people / 2) * 8 + $people * 12; return $total;}

• Call function:

echo movie_price(5);

FooLabWhat Happened?

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Number of people went in

movie_price

Price came outPrice was displayed

(5) echo84

FooLab

Working With Text and NumbersUsing String and Math Functions

FooLabString and Math Functions

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• Open the interactive shell: phpsh

php> echo rand(1, 3);php> echo rand(1, 100);php> echo strlen("FooLab");php> echo substr("FooLab", 3);php> echo substr("FooLab", 3, 1);

FooLabPosition zero

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• Many programming languages start counting at zero.

F o o L a b0advance by: 1 2 3 4 5

FooLabPractice!

• Write a function that calculates a rectangle’s area using height and width.

• Write a function that returns a random letter from the alphabet. Hint: $letters = “abcdefg...”

• substr(text, start, length)

• rand(min, max)

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FooLabAnswer

function area($h, $w) { return $h * $w;}

function rand_letter() { $letters = "abcdefghijklmnopqrstuvwxyz"; return substr($letters, rand(0,25), 1);}

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FooLab

ConditionsIf It’s Cold, Wear a Coat

FooLab

• Expression: produces a value of true or false.

• Execute a process only if the expression is true.

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FooLabWriting Conditional Statements

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• Open the script.php file in your text editor.

$temp = 12;if ($temp < 15) { echo "Wear a coat";}

FooLab

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$temp = 20;if ($temp < 15) { echo "Wear a coat";}else { echo "It's hot enough";}

FooLabMental Exercise

1 < 1

1 == 1

1 != 1

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FooLab

• Temperature is less than 5 degreesandwind is greater than 30 km/h

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Combining Expressions

FooLab

true && true

true && false

true || false

false || false

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Logical Operators

FooLab

RepetitionLather. Rinse. Repeat.

FooLabVocabulary

• Repetition (to repeat)

• Loop (to loop)

• Iteration (to iterate)

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FooLabWriting Loops

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• for (initially ; iterate this time? ; after each iteration)

for ($i = 1; $i <= 3; $i++) { echo $i;}

• $i++ is the same as $i = $i + 1

FooLabWhat Happened?

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$i <= 3

echo $i

$i = 1; $i <= 3; $i++

$i = 2

$i <= 3

echo $i

$i = 3

$i <= 3

echo $i

$i = 4

$i <= 3

stop

FooLabChorus

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for ($i = 1; $i <= 4; $i++) { echo "This song is just six words long\n";}

FooLabArray

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An ordered set of related elements

FooLabArray

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An ordered set of related elements

FooLabWhat Is An Array?

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book page0

page1

page2

number number "Text"

• You can put books in boxes for “nested” arrays,but that’s for another day.

FooLabAcces Elements By Index

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$movies = array("Titanic", "Shrek", "Die Hard");echo $movies[1];

FooLabIterating Over Arrays

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$movies = array("Titanic", "Shrek", "Die Hard");

foreach ($movies as $movie) { echo "I watched $movie\n";}

FooLabGetting Index and Value

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• In addition to the value, you can also get the index for each iteration:

foreach ($movies as $index => $movie)

FooLabConcatenation

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• Link bits of text together using a dot (.)

echo "You rolled " . rand(2, 12);

• Useful in a loop

$sequence = "";for ($i = 1; $i <= 10; $i++) { $sequence = $sequence . rand(0, 9);}echo $sequence;

FooLabPractice!

• Write a function that creates a random 9-character, pronouncable password.

• 3 cyllables, 3 letters each

• Consonant, vowel, consonant

• Should produce something like this:“hagrokwag”

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FooLabAnswerfunction rand_vowel() { $vowels = "aeiou"; return substr($vowels, rand(0,4), 1);}function rand_consonant() { $consonants = "bcdfghjklmnpqrstvwxyz"; return substr($consonants, rand(0,20), 1);}function rand_password() { $pass = ""; for ($i = 1; $i <= 3; $i++ ) { $pass = $pass.rand_consonant().rand_vowel().rand_consonant(); } return $pass;}

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FooLabTrivia

• 6 ^ 21 + 3 ^ 5gives over 20 quadrillions combinations

• It will take millions of years for a computerto try them all

• And you can pronounce it, making it easy to memorize!

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FooLabNext Steps

• Go to phpjunkyard.com

• Download some script

• See how it works

• Play with the code

• Anything you put in /var/www/php1 can be accessed in the browser: http://php1.local/

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FooLabResources

• php.net has a manual and a reference for all functions.

• phpquebec.org is the PHP users group in Montreal.

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