What Is an Operation

This section describes what is an operation - a process that takes one or two operands and returns a result based on certain processing rule represented by the operator.

What Is an Operation? An operation is a process that takes one or two operands and returns a result based on certain processing rule represented by the operator. PHP supports most types of operations used in other programming languages:

1. Bitwise Operations: and ($a & $b), or ($a | $b), xor ($a ^ $b), not (~ $a), shift left ($a << $s), and shift right ($a >> $s).

2. Incrementing/Decrementing Operations: pre-increment (++$a), post-increment ($a++), pre-decrement (--$a), and post-decrement ($a--).

3. Arithmetic Operations: negation (-$a), addition ($a + $b), subtraction ($a - $b), multiplication ($a * $b), division ($a / $b), and modulus ($a % $b).

4. Comparison Operations: equal ($a == $b), identical ($a === $b), not equal ($a != $b, $a <> $b), not identical ($a !== $b), less than ($a < $b), greater than ($a > $b), less than or equal ($a <= $b), and greater than or equal ($a >= $b).

5. Logical Operations: and ($a and $b, $a && $b), or ($a or $b, $a || $b), xor ($a xor $b), and not (!$a).

6. String Operation: concatenation ($a . %b).

7. Assignment Operations: assignment ($a = %b), addition with assignment ($a += $b), subtraction with assignment ($a -= $b), multiplication with assignment ($a *= $b), division with assignment ($a /= $b), modulus with assignment ($a %= $b), and concatenation with assignment ($a .= %b).

To help us understand different types of operations, I wrote the following PHP script, OperationTest.php:

<?php
#  OperationTest.php
#- Copyright 2003 (c) HerongYang.com. All Rights Reserved.
#
   print "\n Bitwise Operations:\n";
   print "    0x00FF & 0x3210: " . (0x00FF & 0x3210) . "\n";
   print "    0x0001 | 0x0010: " . (0x0001 | 0x0010) . "\n";
   print "    0x0001 << 4: " . (0x0001 << 4) . "\n";
   print "    0x0100 >> 4: " . (0x0100 >> 4) . "\n";

   print "\n Incrementing/Decrementing Operations:\n";
   $a = 10; $b = ++$a * 2;
   print "    \$b = ++\$a * 2: $a, $b\n";
   $a = 10; $b = $a++ * 2;
   print "    \$b = \$a++ *2: $a, $b\n";

   print "\n Arithmetic Operations:\n";
   $a = 9; $b = 4;
   print "    \$a * \$b: ". $a * $b . "\n";
   print "    \$a * \$b: ". $a / $b . "\n";
   print "    \$a * \$b: ". $a % $b . "\n";

   print "\n Comparison Operations:\n";
   $a = 9; $b = 4;
   print "    \$a > \$b: ". ($a > $b) . "\n";
   print "    \$a < \$b: ". ($a < $b) . "\n";

   print "\n Logical Operations:\n";
   $a = 9; $b = 4; $c = 1;
   print "    \$a > \$b && \$b > \$c: ". ($a > $b && $b > $c) . "\n";

   print "\n String Operation:\n";
   $name = "Herong"; $greeting = "Hello";
   print "    \$greeting . \$name: ". ($greeting . $name) . "\n";

   print "\n Assignment Operation:\n";
   print "    \$name=\"Herong\": ". ($name="Herong") . "\n";
?>

If you run this sample script, you should get:

herong> \php\php OperationTest.php

 Bitwise Operations:
    0x00FF & 0x3210: 16
    0x0001 | 0x0010: 17
    0x0001 << 4: 16
    0x0100 >> 4: 16

 Incrementing/Decrementing Operations:
    $b = ++$a * 2: 11, 22
    $b = $a++ *2: 11, 20

 Arithmetic Operations:
    $a * $b: 36
    $a * $b: 2.25
    $a * $b: 1

 Comparison Operations:
    $a > $b: 1
    $a < $b:

 Logical Operations:
    $a > $b && $b > $c: 1

 String Operation:
    $greeting . $name: HelloHerong

 Assignment Operation:
    $name="Herong": Herong

Table of Contents

 About This Book

 Introduction and Installation of PHP

 PHP Script File Syntax

 PHP Data Types and Data Literals

 Variables, References, and Constants

Expressions, Operations and Type Conversions

 What Is an Expression

What Is an Operation

 Precedence of Operations

 Data Type Automatic Conversion

 Conditional Statements - "if" and "switch"

 Loop Statements - "while", "for", and "do ... while"

 Function Declaration, Arguments, and Return Values

 Arrays - Ordered Maps

 Interface with Operating System

 Introduction of Class and Object

 Integrating PHP with Apache Web Server

 Retrieving Information from HTTP Requests

 Creating and Managing Sessions in PHP Scripts

 Sending and Receiving Cookies in PHP Scripts

 Controlling HTTP Response Header Lines in PHP Scripts

 Managing File Upload

 MySQL Server Connection and Access Functions

 Functions to Manage Directories, Files and Images

 SOAP Extension Function and Calling Web Services

 SOAP Server Functions and Examples

 Localization Overview of Web Applications

 Using Non-ASCII Characters in HTML Documents

 Using Non-ASCII Characters as PHP Script String Literals

 Receiving Non-ASCII Characters from Input Forms

 "mbstring" Extension and Non-ASCII Encoding Management

 Managing Non-ASCII Character Strings with MySQL Servers

 Parsing and Managing HTML Documents

 Configuring and Sending Out Emails

 Image and Picture Processing

 Managing ZIP Archive Files

 Managing PHP Engine and Modules on macOS

 Managing PHP Engine and Modules on CentOS

 Archived Tutorials

 References

 Full Version in PDF/EPUB