The difference between objects and arrays in php

In PHP, objects and arrays are two common data types. Although they can both be used to store data, they are very different. This article will briefly introduce the difference between objects and arrays in PHP.

1. Definition

In PHP, an array is an ordered collection of data, consisting of a series of key names and corresponding values. Arrays can be created using the array function or, in PHP 5.4 and above, the [] operator.

$fruits = array("apple", "banana", "orange");
$animals = ["dog", "cat", "fish"];

Objects are instances composed of methods and properties and can be created through classes.

class Fruit {
public $name;
public function __construct($name){

<code>$this->name = $name;</code>

}
}

$apple = new Fruit ("apple");

2. Storage method

The key value of the array can be an integer or a string, and it can be continuous or discontinuous. However, objects can only use strings as key names, and attribute names must be unique.

$fruits = ["1" => "apple", "2" => "banana", "3" => "orange"];
echo $fruits["1 "]; //Output apple

$apple = new Fruit("apple");
echo $apple->name; //Output apple

3. Features

1. Characteristics of arrays

(1) You can add, modify, and delete elements at will.

$fruits = ["apple", "banana", "orange"];
$fruits[] = "pear";
$fruits[0] = "grape";
unset($fruits[1]);

(2) Arrays can have multi-dimensional structures.

$fruits = [["apple", "red"], ["banana", "yellow"]];
echo $fruits[0][0]. " is ". $fruits0 ; //Output apple is red

(3) The values ​​in the array can be of any data type.

$fruits = ["apple", 2, true, ["banana"]];
echo gettype($fruits[0]); //Output string
echo gettype($fruits [1]); //Output integer
echo gettype($fruits[2]); //Output boolean
echo gettype($fruits[3]); //Output array

2. Characteristics of objects

(1) Objects have their own methods and properties.

class Fruit {
public $name;
public $color;
public function __construct($name, $color){

<code>$this->name = $name;
$this->color = $color;</code>

}
public function info(){

<code>echo "This ". $this->name. " is ". $this->color;</code>

}
}

$apple = new Fruit("apple", "red");
$apple->info(); / /Output This apple is red

(2) Objects can be inherited.

class Animal {
public $name;
public function __construct($name){

<code>$this->name = $name;</code>

}
}

class Cat extends Animal {
public function sound(){

<code>echo $this->name. " says meow";</code>

}
}

$cat = new Cat("Kitty");
$cat->sound(); //Output Kitty says meow

(3) Objects can implement interfaces.

interface Car {
public function setModel($model);
}

class Audi implements Car {
private $model;
public function setModel($ model){

<code>$this->model = $model;</code>

}
public function getModel(){

<code>echo "The car model is ". $this->model;</code>

}
}

$audi = new Audi();
$ audi->setModel("A4");
$audi->getModel(); //Output The car model is A4

4. Usage scenarios

(1) Arrays are suitable for storing ordered collections, such as lists, calendars, forms, etc.

(2) Objects are suitable for processes that need to solve problems, such as solving problems through encapsulation, or solving problems through techniques such as inheritance and polymorphism.

(3) When accessing database data, an object or array is usually returned. Use objects to access data by calling the object's methods, and use arrays to access data by index or key name.

5. Summary

This article briefly introduces the definition, storage method, characteristics and usage scenarios of objects and arrays in PHP. I believe readers have understood the differences between them and can choose the appropriate data type according to their needs in actual development. No matter which data type you choose, you must pay attention to its reasonable use to improve the readability and maintainability of the program.

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