Cfphp Zce 01 Basics

CFPHP ZCE Training Session One: PHP Basics 1

In Today’s Episode • • PHP Files Summary • • Data Types Useful Resources • Variables & Constants • Operators • Control Structures • Errors 2

PHP Files 3

Scripts • Default Extension: .php • May be Overridden via Server Conf • Not Compiled, Interpreted • Thus, PHP is a text-processing language 4

Tags • Standard Tags • <?php ?> • Short Tags • <? ?> 5

Tags • Script Tags • <script language=“PHP”></script> • ASP Tags • <% %> • * Standard tags are the only recommendation 6

Newlines • Interpreter removes newlines at end of all scripts • This prevents “Headers Already Sent” errors 7

Statement Termination • Semicolons terminate PHP statements • function_call(); • $a = 123; • There are few exceptions • Control Structures • Last Line in PHP Script 8

Comments • // Inline Comment • # PERL Style Comment • /* C Style Multiline Comment */ 9

Whitespace • PHP = Loosely Typed • Whitespace is usually ignored • Exceptions: • Opening/Closing Tags • Keywords • Functions/Variable Names 10

Code Blocks • Deﬁned by { Curly Braces } • Groups code into related blocks • Runs under speciﬁc circumstances • Functions • Conditionals • Loops 11

Language Constructs • Similar to Functions... different rules • if(), while(), for(), foreach(), function() • echo() vs print() • die(), exit() 12

Data Types 13

Data Types • 2 Main Categories • Scalar Values • Compound Values 14

Data Types • Numeric Types • Integer • Floating Point 15

Data Types • Integers • Sined values only • Deﬁned Via • Decimal Notation • Octal Notation • Hexadecimal Notation 16

Data Types • Floating Point • AKA: Doubles, Floats • Deﬁned Via: • Decimal Notation • Exponential Notation 17

Data Types • Strings • Junkdrawers for Binary Data (Usually Text) • Single Quotes = Simple Strings • Double Quotes = Complex Strings • Heredoc = Long Complex Strings 18

Data Types • Booleans • TRUE • FALSE 19

Data Types • Compound Data Types • Array • Object 20

Data Types • Other Data Types • null • Resources 21

Variables & Constants 22

Syntax • Deﬁned by $ • Names may be alpha-numeric • May contain underscores • May NOT begin with a Number 23

Variable Variables • Variable Name becomes a variable • Generally not recommended • Code Difﬁcult to read 24

Variable Existance • isset() 25

Constants • Similar to variables, but not • Values Stored once, may never be changed • Names are suggested to be in ALL_CAPS • deﬁne(), deﬁned() 26

Operators 27

Arithmetic • Addition: + • Subtraction: - • Multiplication: * • Division: / • Modulus: % 28

Arithmetic • Increment Before: ++$a • Increment After: $a++ • Decrement Before: --$a • Decrement After: $a-- 29

String Concatenation • Period is only Concatenation Operator • Two Ways to Concatenate • $c = $a . $b; • $a .= $b; 30

Assignment • Simple Assignment • Arithmetic/Bitwise Assignment • $a += $b; • $a *= $b; 31

References • $a = 4; $b = $a; $a = 6; echo $b; 32

References • $a = 4; $b &= $a; $a = 6; echo $b; 33

References • Scalar Values and Arrays are always COPIED • Objects are Passed Via Reference 34

Comparison • Results of Comparison Operations are ALWAYS boolean • Equal == • Identical === • Not Equal != • Not Identical !== 35

Comparison • Less Than < • Greater Than > • Less Than or Equal To <= • Greater Than or Equal To >= 36

Logical • NOT ! • AND && / and • OR || / or • XOR 37

Other • Error Control Operator @ • @mysql_connect(‘foo’, ‘bar’, ‘beer’); • Backtick • $a = `ls -la`; 38

Control Structures 39

Conditionals • if • else • elseif • Ternary • $a = (isset($b)) : ‘mike’ ? ‘chris’; 40

Loops • while • do...while • for • break / continue 41

Errors 42

Error Levels • Compile Time • Errors occured during script compilation. • Script execution is halted 43

Error Levels • Fatal Errors • Errors in syntax, etc. • Script execution is halted 44

Error Levels • Recoverable Errors • Signiﬁcant failures • Can still run in a safe way 45

Error Levels • Warnings • Recoverable errors. • Script execution continues 46

Error Levels • Notices • Generally small errors. IE Undeﬁned variables, etc. • Script execution continues 47

Error Reporting • php.ini Directives • error_reporting • display_errors • log_errors 48

Handling Errors • set_error_handler() 49

Questions? 50

Useful Resources 51

Reading • ZEND PHP 5 Certiﬁcation Study Guide http://www.phparch.com/shop_product.php?itemid=135 • Programming PHP http://en.wikibooks.org/wiki/PHP • Practical PHP Programming http://hudzilla.org/phpwiki/index.php?title=Main_Page • The PHP Manual http://us2.php.net/manual/en/ 52

Cfphp Zce 01 Basics

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