Can the elements of a php array be numbers?

The elements of the php array can be numbers. Because PHP is a programming language with weak data types, arrays in PHP can store any number of data of any type, that is, there is no limit on the type of array elements, which can be numbers (integers and floating point numbers), strings, Boolean values, Types such as arrays and Object objects.

The operating environment of this tutorial: windows7 system, PHP version 8.1, DELL G3 computer

The elements of the php array can be numbers .

Array is one of the most important data types in PHP and is widely used in PHP. Because PHP is a programming language with weak data types, array variables in PHP can store any number of data of any type, and can implement the functions of data structures such as heaps, stacks, and queues in other strong data types.

Simply put, there is no restriction on the type of PHP array elements, which can be numbers, strings, Boolean values, arrays, Object objects, etc.

Example 1: Index array

<?php
header("Content-type:text/html;charset=utf-8");
$arr= array(1,2,"3",4,0.5,"hello",TRUE,3.14);
var_dump($arr);
?>

Explanation: The subscript (key name) of the index array consists of numbers, starting from 0 by default. Each number corresponds to the position of an array element in the array. There is no need to specify it. PHP will automatically assign an integer value to the key name of the index array, and then automatically increase from this value.

Example 2: Associative array

<?php
header("Content-type:text/html;charset=utf-8");
$arr=array(1=>1,"a"=>3.5,2=>2,"b"=>0,"c"=>"blue");
var_dump($arr);
?>

Explanation: The subscript (key name) of the associative array consists of a mixture of numerical values ​​and strings. If a If a key in the array is not a number, then the array is an associative array.

Numbers in php

In php, numbers can be divided into integer (integer type) and float (floating point type)

Type	Function
integer (integer type)	Integer type contains all integers, which can be positive numbers or It is a negative number
float (floating point type)	The floating point type is also used to represent numbers. Unlike the integer type, it can also be used to represent integers. Representing decimals and exponents

1) Integer type

In PHP, integer variables are called integer or int types, which are used to represent an integer. The rules of the type are as follows:

• The integer type must have at least one number (0~9);

• The integer type cannot contain commas or Space;

• The integer type cannot contain a decimal point;

• The integer type can be a positive or negative number.

The value range of the integer type must be between -2E31 and 2E31, and can be expressed in three formats, namely decimal, hexadecimal (prefixed with 0x) and Octal (prefixed with 0).

<?php
    $x = 5985;      // 定义一个整型数据类型的变量
    var_dump($x);   // 输出此变量
    $x = -345;
    var_dump($x);   
    $x = 0x8C;      //十六进制数字
    var_dump($x); 
    $x = 047;       //八进制数字
    var_dump($x);
?>

Note that in the PHP7 version, strings containing hexadecimal characters are no longer treated as numbers, but as ordinary strings.

2) Floating point type

The floating point type is called the float type in PHP, and can also be called real numbers. It can be used to store integers and decimals. The valid value range is 1.8 Between E-308 and 1.8E 308. Floating point numbers have higher precision than integer data types.

<?php
    $num1 = 10.365;
    $num2 = 2.4e3;
    $num3 = 8E-5;
    var_dump($num1, $num2, $num3);
?>

Recommended learning: "PHP Video Tutorial"

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