What does int mean in php?

Integer in php refers to the Integer type, and int is a number in the set "ℤ = {..., -2, -1, 0, 1, 2, ...}", integer The type value int can be expressed in decimal, hexadecimal, octal or binary, such as "$a = 1234;".

The operating environment of this article: Windows 7 system, PHP version 7.1, DELL G3 computer

What does int mean in php?

Integer integer type

int is in the set ℤ = {..., -2, -1, 0, 1, 2, ...} a certain number.

Syntax

The integer value int can be expressed in decimal, hexadecimal, octal or binary, and can be preceded by an optional symbol (- or ). You can use the negative operator to represent a negative int.

To use octal expression, 0 (zero) must be added before the number. Starting from PHP 8.1.0, octal expressions can also be preceded by 0o or 0O . To use hexadecimal representation, the number must be preceded by 0x. To use binary representation, the number must be preceded by 0b.

Starting from PHP 7.4.0, integer values ​​may contain underscores (_). For a better reading experience, these underscores will be filtered out by PHP when displayed.

Example #1 Integer literal expression

<?php
$a = 1234; // 十进制数
$a = 0123; // 八进制数 (等于十进制 83)
$a = 0o123; // 八进制数 (PHP 8.1.0 起)
$a = 0x1A; // 十六进制数 (等于十进制 26)
$a = 0b11111111; // 二进制数字 (等于十进制 255)
$a = 1_234_567; // 整型数值 (PHP 7.4.0 以后)
?>

The structure of the int syntax is (underscores are not supported before PHP 7.4.0):

decimal     : [1-9][0-9]*(_[0-9]+)*
            | 0
hexadecimal : 0[xX][0-9a-fA-F]+(_[0-9a-fA-F]+)*
octal       : 0[oO]?[0-7]+(_[0-7]+)*
binary      : 0[bB][01]+(_[01]+)*
integer     : decimal
            | hexadecimal
            | octal
            | binary

The word length of the integer int Platform dependent, although usually the maximum is about two billion (32-bit signed). The maximum value on 64-bit platforms is usually around 9E18. PHP does not support unsigned int. The word length of an int value can be represented by the constant PHP_INT_SIZE, the maximum value can be represented by the constant PHP_INT_MAX, and the minimum value can be represented by the constant PHP_INT_MIN.

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