Introduction to PHP

n      Open Source

n      Server-side scripts

n      Installing PHP

      So many blogs with LAMP setting up, of course you can refer to http://blog.csdn.net/wildhorseli/archive/2006/07/20/947479.aspx

 

n      Now, it is time to say “hello world”

Language Basics (Lexical Structure)

n      Case sensitivity

Ø           Classes, functions of user-defined are case-insensitive

Ø              Variables are case sensitive

n      Statements and semicolons

Ø      The semicolon is optional before a closing PHP

    eg <?php echo “Enjoy PHP” ?>

n      Comments

Ø      Shell-style comments, with a hash mark; it sometimes is used to mark off blocks of codes: eg

   ##################

   ##Happy Functions

   ##################

Ø      C++ comments, with two slash characters //  to comment on code: eg

    //Check if there is enough money

    if( money > $10w )

Ø      C comments, multiline comment

 

 

Language Basics (Lexical Structure)

n      Identifier

Ø      Only scalar valuesBoolean, integer, double, and stringcan be constants

Ø      Using define function

n      Keywords case-insensitive

 

Ø        _ _CLASS_ _cloneendif_ _FILE_ _Constendswitch_ _FUNCTION_ _Continueendwhile_ _LINE_ _Declareeval( )_ _METHOD_ _DefaultexceptionAbstractdie( )exit( )AndDoextendsarray( )echo( )extendsAsElsefinalBreakelseifforCaseempty( )foreachcatchenddeclarefunctioncfunctionendforglobalClassendforeachifimplementsphp_user_filterswitchinclude( )print( )tHRowinclude_once( )privateTRyinterfaceprotectedunset( )isset( )publicuselist( )require( )varnewrequire_once( )whileold_functionreturn( )xorOrstatic

Language Basics (Data Types)

n      Introduction

Ø      PHP provides eight types of values, or data types. Four are scalar (single-value) types: integers , floating-point numbers, strings, and Booleans. Two are compound (collection) types: arrays and objects

n      Integers

Ø      Use is_int() to test whether a value is integer

n      Floating-Point Numbers

Ø      Use is_float() to test whether a value is float

n      Strings

Ø      Variables are expanded within double quotes, while within single quotes they are not: $name=“Martin”; echo “Hi, $name”; echo ‘Hi, $name’;

Ø      Double quotes also support a variety of string escapes, such as /” /n /r /t // /$ /{ /[

n      Booleans (false)

Ø      The keyword false

Ø      0

Ø      0.0

Ø      “” and “0”

Ø      An array with zero elements

Ø      An object with no values or functions

Ø      NULL

 

 

Language Basics (Data Types)

n      Arrays

Ø      Loop through arrays

    1 foreach( $person as $name)

         echo “hello, $name”;

    2 foreach( $creator as @key=>$value)

Ø      Sort($array) asort($array)

Ø      Use the is_array() function to test whether a value is an array.

n      Objects

Ø      Use is_object() to test whether a value is an object

Ø      More reference, see the following

n      Resources

Ø      Like a “handle”

n      NULL

Ø      No value

Ø      Case –insensitive

Ø      Is_null()

Language Basics (Variables)

n      Variable variables

Ø      Eg $foo = ‘bar’;

           $$foo = ‘baz’;    // $bar = ‘baz’;

n      Variable References

Ø      &

Ø      More info, refer to function section

n      Variable Scope

Ø      Local scope

      by default, variables defined outside a function are not accessible inside the function

Ø      Global scope

      use the global keyword inside the function to declare the variable within the function. { global $counter; }

Ø      Static variables

      only useful for the function.

Ø      Function parameters

       function parameters are local.   

n      Garbage Collection

Ø      Copy-on-write  change one, copy two

Ø      Isset() To see if empty, string is suited

Ø      unset()

Language Basics (Expressions and Operators)

n      .

Ø      String

n      operator

Ø      + ..    “9 Jo” +1 = 10

n      Comparison

 

 

 

 

n      Casting

Ø      (int)(object)(array)

Language Basics (Others)

n      Declare

 

n      Exit return

Ø      die

Ø      return

n      Include code

Ø      require

      such as html

Ø      include

     

Functions (Function parameters)

n      Passing Parameters by value

Ø      In most cases

n      Passing Parameters by Reference

Ø      The argument must be a variable

Ø      &

n      Default Parameters

Ø      Assign the parameter value in the function declare

Ø      The value can only be a constant

n      Variable Parameters

Ø      $array = func_get_args()

Ø      $count = func_num_args()

Ø      $value = func_get_arg(argument_number)

 

n      Missing Parameters

Ø      Lets you be as lazy

Ø      Remain unset

 

 

 

 

Functions (Others)

n    Return Values

Ø     Single value

Ø     Array

n    Variable Functions

Ø     function_exists()

n    Anonymous Functions

Ø     Create_function

 

 

Strings (Quoting String Constants)

n    Variable Interpolation

Ø     Using double quotes

      echo “$variable hello”;

      echo “{$n}th”;

Ø     Using single quote

        escape sequences: /’   //

n    Here Documents

Ø     $variable = <<< Name

                Name;

 

 

 

Strings (Printing Strings)

n    echo

Ø     echo “”

Ø     Echo(“”)

Ø     echo ”a”,”b”  commas

Ø     No return

n    Print

Ø     Print one value

Ø     Return a boolean value

n    printf

Ø     Format modifiers

n    Print_r & var_dump

Ø     Print_r() means objects tostring()

Ø     Var_dump for debuging