"if" Statement Examples

This section provides a tutorial example on how to use different types of 'if' statements to control code executions.

To help us understand how "if" statements work, I wrote the following the tutorial example PHP script:

#  IfStatements.php
#- Copyright (c) HerongYang.com. All Rights Reserved.

   print("\n Single-statement \"if\":\n");
   $isNewYear = TRUE;
   if ($isNewYear) print("    Happy New Year!\n");

   print("\n Multi-statement \"if\":\n");
   $hasError = TRUE;
   if ($hasError) {
      print("    Open the log file.\n");
      print("    Write an error message.\n");
      print("    Close the log file.\n");

   print("\n \"if ... else\" statement:\n");
   $login = "Herong";
   if ($login == "Admin") {
      print("    Display the delete button.\n");
      print("    Display the edit button.\n");
   } else {
      print("    Display the view button.\n");

   print("\n \"if ... elseif\" statement:\n");
   $dateInfo = getdate();
   $wDay = $dateInfo["wday"];
   $weekDay = $dateInfo["weekday"];
   $openHours = "open";
   if ($wDay == 0) {
      $openHours = "closed";
   } elseif ($wDay >= 1 && $wDay <= 5) {
      $openHours = "open from 9:00am to 9:00pm";
   } elseif ($wDay == 6 ) {
      $openHours = "open from 9:00am to 5:00pm";
   } else {
      $openHours = "not at here";
   print("    Today is: $weekDay\n");
   print("    The library is $openHours\n");

If you run this sample script, you should get:

C:\herong> \php\php IfStatements.php

 Single-statement "if":
    Happy New Year!

 Multi-statement "if":
    Open the log file.
    Write an error message.
    Close the log file.

 "if ... else" statement:
    Display the view button.

 "if ... elseif" statement:
    Today is: Sunday
    The library is closed

Table of Contents

 About This Book

 Introduction and Installation of PHP 7.3

 PHP Script File Syntax

 PHP Data Types and Data Literals

 Variables, References, and Constants

 Expressions, Operations and Type Conversions

Conditional Statements - "if" and "switch"

 "if" Statements

"if" Statement Examples

 "switch" Statements

 "switch" Statement Examples

 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

 Outdated Tutorials


 Full Version in PDF/EPUB