1. php
  2. /basics
  3. /data-types

Introduction to PHP data-types

List of Data Types

In PHP, there are several data types that can be used to store different types of values. Some common data types include:

  1. Integer: A whole number, such as -5, 0, or 25.

  2. Float: A decimal number, such as 3.14 or -0.5.

  3. String: A sequence of characters, such as "Hello World!" or "John Smith".

  4. Boolean: A true or false value, used for conditional statements and logic.

  5. Array: A collection of values that can be accessed by an index or key.

  6. Object: An instance of a class, which can have properties and methods.

  7. NULL: A value that represents the absence of a value.

  8. Resource: A special type of data that represents a connection to an external resource, such as a file or database connection.

  9. Callback: A function or method that can be passed as an argument to another function.

  10. Mixed: A variable that can store different types of data, such as integers, strings, or arrays.


Here are examples of how some of the PHP data types can be used:

// Integer
$age = 25;

// Float
$pi = 3.14;

// String
$name = "John Smith";

// Boolean
$isStudent = true;

// Array
$colors = array("red", "green", "blue");

// Object
class Person {
    public $name;
    public $age;
$person = new Person();
$person->name = "Jane Doe";
$person->age = 30;

$address = NULL;

// Resource
$file = fopen("example.txt", "r");

// Callback
function sayHello() {
    echo "Hello World!";
$callback = "sayHello";

// Mixed
$mixed = "Hello";
$mixed = 35;
$mixed = array(1, 2, 3);

In this example, we can see different data types being used in different ways. We can assign different values to different variables using different data types and call them in the program as per the requirement.

Best Practices

  1. Always use the appropriate data type for the information you are storing. For example, use integers for whole numbers and floats for decimal numbers.

  2. Use proper variable naming conventions. For example, use camelCase for variable names and start variable name with lowercase letter.

  3. Avoid using hardcoded values in your code. Instead, use constants or variables to store values that may change in the future.

  4. When working with strings, make sure to use the appropriate string functions for the task at hand. For example, use the strlen() function to find the length of a string and str_replace() to replace a specific substring.

  5. Be mindful of the size and memory usage of your arrays. Use the appropriate data structures, such as linked lists or hash tables, to optimize performance.

  6. When working with objects, take advantage of the object-oriented features of PHP, such as inheritance and polymorphism.

  7. Use NULL values appropriately, to indicate when a variable has no value assigned to it.

  8. When working with resources, make sure to close them properly when they are no longer needed.

  9. When working with callbacks, make sure that the function or method being passed as a callback is valid and can be called.

  10. Be consistent in your data types usage, avoid mixing data types for the same kind of information, for example, don't use string for storing age and integer for storing name.