Integer integer type
An integer is a number in the set ? = {..., -2, -1, 0, 1, 2, ...}.
See:
Arbitrary length integer/GMP
Floating point type
Arbitrary precision math library/BCMath
Syntax
Integer values can use decimal, hexadecimal base, octal Or binary representation, preceded by an optional symbol (- or +).
Binary representation of integer is available since PHP 5.4.0.
To use octal expression, 0 (zero) must be added before the number. To use hexadecimal expression, the number must be preceded by 0x. To use binary representation, 0b must be added before the number.
Example #1 Integer literal expression
<?php $a = 1234; // 十进制数 $a = -123; // 负数 $a = 0123; // 八进制数 (等于十进制 83) $a = 0x1A; // 十六进制数 (等于十进制 26) ?>
The formal description of integer is:
decimal : [1-9][0-9]*
| 0
hexadecimal : 0[xX][0-9a-fA-F]+
octal : 0[0-7]+
binary : 0b[01]+
integer : [+-]?decimal
| [+- ]?hexadecimal
hexadecimal . The maximum value on a 64-bit platform is usually around 9E18. PHP does not support unsigned integers. The word length of the Integer value can be represented by the constant PHP_INT_SIZE. Since PHP 4.4.0 and PHP 5.0.5, the maximum value can be represented by the constant PHP_INT_MAX.
If an illegal number (i.e. 8 or 9) is passed to an octal number, the remaining digits will be ignored.
Example #2 Strange things about octal numbers
<?php var_dump(01090); // 八进制 010 = 十进制 8 ?>
Integer overflow
If a given number exceeds the range of integer , it will be interpreted as float. Similarly, if the result of the operation exceeds the range of integer, float will be returned.
Example #3 Integer overflow under 32-bit system
<?php $large_number = 2147483647; var_dump($large_number); // int(2147483647) $large_number = 2147483648; var_dump($large_number); // float(2147483648) $million = 1000000; $large_number = 50000 * $million; var_dump($large_number); // float(50000000000) ?> Example #4 64 位系统下的整数溢出 <?php $large_number = 9223372036854775807; var_dump($large_number); // int(9223372036854775807) $large_number = 9223372036854775808; var_dump($large_number); // float(9.2233720368548E+18) $million = 1000000; $large_number = 50000000000000 * $million; var_dump($large_number); // float(5.0E+19) ?>
There is no integer division operator in PHP. 1/2 yields float 0.5. The value can be cast to an integer, discarding the fractional part, or using the round() function for better rounding.
<?php var_dump(25/7); // float(3.5714285714286) var_dump((int) (25/7)); // int(3) var_dump(round(25/7)); // float(4) ?>
Convert to integer
To explicitly convert a value to an integer, cast with (int) or (integer) . In most cases, however, casting is not necessary because when an operator, function, or flow control requires an integer parameter, the value is automatically converted. You can also use the function intval() to convert a value into an integer.
See: Discrimination of type conversion.
Converting from a Boolean value
FALSE will produce 0 (zero), TRUE will produce 1 (one).
Converting from Float
When converting from a floating point number to an integer, it will be rounded down.
If the floating point number exceeds the integer range (usually +/- 2.15e+9 = 2^31 on 32-bit platforms, +/- 9.22e+18 = 2^63 on 64-bit platforms), The result is undefined because there is insufficient precision to give an exact integer result. There is no warning in this case, not even any notification!
Never cast an unknown fraction to an integer, as this can sometimes lead to unpredictable results.
<?php echo (int) ( (0.1+0.7) * 10 ); // 显示 7! ?>
See warning about floating point precision.
Convert from string
See Convert string to numeric value.
Converting from other types
Caution

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

SublimeText3 Linux new version
SublimeText3 Linux latest version

SublimeText3 Chinese version
Chinese version, very easy to use