Essential Methods for PHP Classes: A Comprehensive Guide
☰Fullscreen
Table of Content:
- The functions which are declared in a class are called methods.
- A class method is exactly similar to PHP functions.
- Declaring a method in a class is an easy task, use one of the keyword public, protected, or private followed by a method name.
- public: The method can be accessed from outside the class.
- private: No access is granted from outside the class.
- protected: No access is granted from outside the class except a class that’s a child of the class with the protected property or method.
- A valid method name starts with a letter or underscores, followed by any number of letters, numbers, or underscores.
- The method body enclosed within a pair of braces that contain codes. The opening curly brace ( { ) indicates the beginning of the method code and the closing curly ( } ) brace indicates the termination of the method.
- If the method is not defined by the public, protected, or private then the default is public.
- Can access properties and methods of the current instance using $this (Format $this->property) for a non-static property.
Example:
After an object is instantiated, you can access the method of a class using the object and -> operator. In the following example customize_print() method will print a string with specific font size and color within an HTML paragraph element with the help of the PHP echo statement.
Syntax
<span class="pln"> </span><span class="pun"><?</span><span class="pln">php </span><span class="kwd">class</span><span class="pln"> </span><span class="typ">Myclass</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> </span><span class="kwd">public</span><span class="pln"> $font_size </span><span class="pun">=</span><span class="str">"18px"</span><span class="pun">;</span><span class="pln"> </span><span class="kwd">public</span><span class="pln"> $font_color </span><span class="pun">=</span><span class="pln"> </span><span class="str">"blue"</span><span class="pun">;</span><span class="pln"> </span><span class="kwd">public</span><span class="pln"> $string_name </span><span class="pun">=</span><span class="pln"> </span><span class="str">"atnyla"</span><span class="pun">;</span><span class="pln"> </span><span class="kwd">public</span><span class="pln"> </span><span class="kwd">function</span><span class="pln"> customize_print</span><span class="pun">()</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> echo </span><span class="str">"<p style=font-size:"</span><span class="pun">.</span><span class="pln">$this</span><span class="pun">-></span><span class="pln">font_size</span><span class="pun">.</span><span class="str">";color:"</span><span class="pun">.</span><span class="pln">$this</span><span class="pun">-></span><span class="pln">font_color</span><span class="pun">.</span><span class="str">";>"</span><span class="pun">.</span><span class="pln">$this</span><span class="pun">-></span><span class="pln">string_name</span><span class="pun">.</span><span class="str">"</p>"</span><span class="pun">;</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> $f </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">MyClass</span><span class="pun">;</span><span class="pln"> echo $f</span><span class="pun">-></span><span class="pln">customize_print</span><span class="pun">();</span><span class="pln"> </span><span class="pun">?></span><span class="pln"> </span>
Now change the value of font_size, font_color, and the string and check what the method custimize_print() returns.
Syntax
<span class="pln"> </span><span class="pun"><?</span><span class="pln">php </span><span class="kwd">class</span><span class="pln"> </span><span class="typ">Myclass</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> </span><span class="kwd">public</span><span class="pln"> $font_size </span><span class="pun">=</span><span class="str">"18px"</span><span class="pun">;</span><span class="pln"> </span><span class="kwd">public</span><span class="pln"> $font_color </span><span class="pun">=</span><span class="pln"> </span><span class="str">"blue"</span><span class="pun">;</span><span class="pln"> </span><span class="kwd">public</span><span class="pln"> $string_name </span><span class="pun">=</span><span class="pln"> </span><span class="str">"w3resource"</span><span class="pun">;</span><span class="pln"> </span><span class="kwd">public</span><span class="pln"> </span><span class="kwd">function</span><span class="pln"> customize_print</span><span class="pun">()</span><span class="pln"> </span><span class="pun">{</span><span class="pln"> echo </span><span class="str">"<p style=font-size:"</span><span class="pun">.</span><span class="pln">$this</span><span class="pun">-></span><span class="pln">font_size</span><span class="pun">.</span><span class="str">";color:"</span><span class="pun">.</span><span class="pln">$this</span><span class="pun">-></span><span class="pln">font_color</span><span class="pun">.</span><span class="str">";>"</span><span class="pun">.</span><span class="pln">$this</span><span class="pun">-></span><span class="pln">string_name</span><span class="pun">.</span><span class="str">"</p>"</span><span class="pun">;</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> $f </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">MyClass</span><span class="pun">;</span><span class="pln"> $f</span><span class="pun">-></span><span class="pln">font_size </span><span class="pun">=</span><span class="pln"> </span><span class="str">"20px"</span><span class="pun">;</span><span class="pln"> $f</span><span class="pun">-></span><span class="pln">font_color </span><span class="pun">=</span><span class="pln"> </span><span class="str">"red"</span><span class="pun">;</span><span class="pln"> $f</span><span class="pun">-></span><span class="pln">string_name </span><span class="pun">=</span><span class="pln"> </span><span class="str">"Object Oriented Programming"</span><span class="pun">;</span><span class="pln"> echo $f</span><span class="pun">-></span><span class="pln">customize_print</span><span class="pun">();</span><span class="pln"> </span><span class="pun">?></span><span class="pln"> </span>
Another Example:
Example Code:
<span class="pln"> </span><span class="pun"><?</span><span class="pln">php </span><span class="kwd">class</span><span class="pln"> </span><span class="typ">Dress</span><span class="pun">{</span><span class="pln"> </span><span class="kwd">public</span><span class="pln"> $color </span><span class="pun">=</span><span class="pln"> </span><span class="str">"red"</span><span class="pun">;</span><span class="pln"> </span><span class="com">// The color of the dress </span><span class="pln"> </span><span class="typ">Public</span><span class="pln"> $fabric </span><span class="pun">=</span><span class="pln"> </span><span class="str">"linen"</span><span class="pun">;</span><span class="pln"> </span><span class="com">// The fabric of the dress </span><span class="pln"> </span><span class="typ">Public</span><span class="pln"> $design </span><span class="pun">=</span><span class="pln"> </span><span class="str">"Slim Fit Blazer"</span><span class="pun">;</span><span class="com">//The design of the dress </span><span class="pln"> </span><span class="typ">Public</span><span class="pln"> </span><span class="kwd">function</span><span class="pln"> displayInfo</span><span class="pun">(){</span><span class="pln"> echo </span><span class="str">"The info about the dress.</br>"</span><span class="pun">;</span><span class="pln"> echo $this</span><span class="pun">-></span><span class="pln">color</span><span class="pun">.</span><span class="str">"</br>"</span><span class="pun">;</span><span class="pln"> echo $this</span><span class="pun">-></span><span class="pln">fabric</span><span class="pun">.</span><span class="str">"</br>"</span><span class="pln"> </span><span class="pun">;</span><span class="pln"> echo $this</span><span class="pun">-></span><span class="pln">design</span><span class="pun">.</span><span class="str">"</br>"</span><span class="pun">;</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> $dressObj </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">Dress</span><span class="pun">();</span><span class="pln"> $dressObj</span><span class="pun">-></span><span class="pln">displayInfo</span><span class="pun">();</span><span class="pln"> </span><span class="pun">?></span><span class="pln"> </span>
Example of this keyword
Example Code:
<span class="pln"> </span><span class="pun"><?</span><span class="pln">php </span><span class="kwd">class</span><span class="pln"> </span><span class="typ">Dress</span><span class="pun">{</span><span class="pln"> </span><span class="kwd">public</span><span class="pln"> $color </span><span class="pun">=</span><span class="pln"> </span><span class="str">"red"</span><span class="pun">;</span><span class="pln"> </span><span class="com">// The color of the dress </span><span class="pln"> </span><span class="typ">Public</span><span class="pln"> $fabric </span><span class="pun">=</span><span class="pln"> </span><span class="str">"linen"</span><span class="pun">;</span><span class="pln"> </span><span class="com">// The fabric of the dress </span><span class="pln"> </span><span class="typ">Public</span><span class="pln"> $design </span><span class="pun">=</span><span class="pln"> </span><span class="str">"Slim Fit Blazer"</span><span class="pun">;</span><span class="com">//The design of the dress </span><span class="pln"> </span><span class="typ">Public</span><span class="pln"> </span><span class="kwd">function</span><span class="pln"> displayInfo</span><span class="pun">(){</span><span class="pln"> echo </span><span class="str">"The info about the dress.</br>"</span><span class="pun">;</span><span class="pln"> echo $this</span><span class="pun">-></span><span class="pln">color</span><span class="pun">.</span><span class="str">"</br>"</span><span class="pun">;</span><span class="pln"> echo $this</span><span class="pun">-></span><span class="pln">fabric</span><span class="pun">.</span><span class="str">"</br>"</span><span class="pln"> </span><span class="pun">;</span><span class="pln"> echo $this</span><span class="pun">-></span><span class="pln">design</span><span class="pun">.</span><span class="str">"</br>"</span><span class="pun">;</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> </span><span class="typ">Public</span><span class="pln"> </span><span class="kwd">function</span><span class="pln"> helloWorld</span><span class="pun">(){</span><span class="pln"> echo $this</span><span class="pun">-></span><span class="pln">displayInfo</span><span class="pun">();</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> $dressObj </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">Dress</span><span class="pun">();</span><span class="pln"> $dressObj</span><span class="pun">-></span><span class="pln">helloWorld</span><span class="pun">();</span><span class="pln"> </span><span class="pun">?></span><span class="pln"> </span>
Example of parameterized function
Example Code:
<span class="pln"> </span><span class="pun"><?</span><span class="pln">php </span><span class="kwd">class</span><span class="pln"> </span><span class="typ">Dress</span><span class="pun">{</span><span class="pln"> </span><span class="kwd">public</span><span class="pln"> $color </span><span class="pun">=</span><span class="pln"> </span><span class="str">"red"</span><span class="pun">;</span><span class="pln"> </span><span class="com">// The color of the dress </span><span class="pln"> </span><span class="typ">Public</span><span class="pln"> $fabric </span><span class="pun">=</span><span class="pln"> </span><span class="str">"linen"</span><span class="pun">;</span><span class="pln"> </span><span class="com">// The fabric of the dress </span><span class="pln"> </span><span class="typ">Public</span><span class="pln"> $design </span><span class="pun">=</span><span class="pln"> </span><span class="str">"Slim Fit Blazer"</span><span class="pun">;</span><span class="com">//The design of the dress </span><span class="pln"> </span><span class="typ">Public</span><span class="pln"> </span><span class="kwd">function</span><span class="pln"> displayInfo</span><span class="pun">(){</span><span class="pln"> echo </span><span class="str">"The info about the dress."</span><span class="pun">;</span><span class="pln"> echo $this</span><span class="pun">-></span><span class="pln">color</span><span class="pun">;</span><span class="pln"> echo $this</span><span class="pun">-></span><span class="pln">fabric </span><span class="pun">;</span><span class="pln"> echo $this</span><span class="pun">-></span><span class="pln">design</span><span class="pun">;</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> </span><span class="typ">Public</span><span class="pln"> </span><span class="kwd">function</span><span class="pln"> helloWorld</span><span class="pun">(</span><span class="pln">$number1</span><span class="pun">,</span><span class="pln"> $number2</span><span class="pun">){</span><span class="pln"> </span><span class="kwd">return</span><span class="pln"> $number1 </span><span class="pun">+</span><span class="pln"> $number2</span><span class="pun">;</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> </span><span class="pun">}</span><span class="pln"> $dressObj </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">Dress</span><span class="pun">();</span><span class="pln"> echo $dressObj</span><span class="pun">-></span><span class="pln">helloWorld</span><span class="pun">(</span><span class="lit">20</span><span class="pun">,</span><span class="lit">30</span><span class="pun">);</span><span class="pln"> </span><span class="pun">?></span><span class="pln"> </span>
No Questions Data Available.
- Assignment 1: Simple Calculator using PHP
- Assignment 2: PHP Program - Write a function to calculate the factorial of a number (a non-negative integer). The function accepts the number as an argument.
- Assignment 3: Write a PHP function to generate a random password. The password should contain uppercase, lowercase, numeric and other