Learn PHP with Me

PHP - Hypertext Preprocessor
Version - PHP 5
Uses:

  • Generate dynamic page content
  • Create/Read/Open/Delete/Write/Close files on Server
  • Collect form Data
  • Send/Recieve Cookies
  • Add/Delete/Modify Data in DB
  • User Access Control
  • DataEncryption
  • Free/easy/compatible on all servers,runs on various platforms.
Installation: (MAMP server includes Apache+MySQL)
Install MAMP server on your pc and start coding PHP.
Place php files in htdocs directory of MAMP installation folder and play around.

Basics:
syntax:
<?php
   echo "Praise the Lord!";
?>

comments : // or */ blah blah /*
variables : case senstive
    $my_num = 12345678;
    $my_name = Hanvitha;
strings : use . for concatenating 
echo "My name is " . $my_name;
strlen, strpos, strrev, str_word_count, str_replace
scope: 
   local -  
   global - global $x, $y;
    $GLOBALS['y'] = $GLOBALS['x'] + $GLOBALS['y'];
   static - 
objects -
   class A{ function A(){ $this->x = "blah"; }
   $my_A = new A();
   echo $my_A->x;
constants: they are global
  no $ sign before a constant - created by :define("GREETING", "Welcome to my page"); echo GREETING;
operators: $x ** $y; === Identity; <> inequality; !== non identity;
rest are same as Java/C++
conditions & loops : all are same like Java/C++ except
      foreach($colorsArray as $color){  echo "$color<br>";   }
functions: 
   function writeMsg() {
      echo "Hello world!";
   }
   writeMsg();
arrays:
  $bible_chapters= array("Genesis", "Deuteronomy" , "Numbers" ...);
    echo "I love $bible_chapters[0] where God created Earth";
  $books = count($bible_chapters);
  associate arrays: $age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");

Super Globals :
  1. $_SERVER is a PHP super global variable which holds information about headers, paths, and script locations.
  2. $_REQUEST is used to collect data after submitting an HTML form.
  3. $_POST is widely used to collect form data after submitting an HTML form with method="post". $_POST is also widely used to pass variables.
  4. $_GET can also be used to collect form data after submitting an HTML form with method="get".

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