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rand

(PHP 4, PHP 5, PHP 7)

rand — Generate a random integer

Description

代码语言:javascript
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int rand ( void )
代码语言:javascript
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int rand ( int $min , int $max )

If called without the optional min, max arguments rand() returns a pseudo-random integer between 0 and getrandmax(). If you want a random number between 5 and 15 (inclusive), for example, use rand(5, 15).

Caution

This function does not generate cryptographically secure values, and should not be used for cryptographic purposes. If you need a cryptographically secure value, consider using random_int(), random_bytes(), or openssl_random_pseudo_bytes() instead.

Note: On some platforms (such as Windows), getrandmax() is only 32767. If you require a range larger than 32767, specifying min and max will allow you to create a range larger than this, or consider using mt_rand() instead.

Note: As of PHP 7.1.0, rand() uses the same random number generator as mt_rand(). To preserve backwards compatibility rand() allows max to be smaller than min as opposed to returning FALSE as mt_rand().

Parameters

min

The lowest value to return (default: 0)

max

The highest value to return (default: getrandmax())

Return Values

A pseudo random value between min (or 0) and max (or getrandmax(), inclusive).

Changelog

Version

Description

7.1.0

rand() has been made an alias of mt_rand().

Examples

Example #1 rand() example

代码语言:javascript
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<?php
echo?rand()?.?"\n";
echo?rand()?.?"\n";

echo?rand(5,?15);
?>

The above example will output something similar to:

代码语言:javascript
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7771
22264
11

Notes

Warning

min max range must be within the range getrandmax(). i.e. (max - min) <= getrandmax() Otherwise, rand() may return poor-quality random numbers.

See Also

  • srand() - Seed the random number generator
  • getrandmax() - Show largest possible random value
  • mt_rand() - Generate a random value via the Mersenne Twister Random Number Generator
  • random_int() - Generates cryptographically secure pseudo-random integers
  • random_bytes() - Generates cryptographically secure pseudo-random bytes
  • openssl_random_pseudo_bytes() - Generate a pseudo-random string of bytes

← rad2deg

round →

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 ? 1997–2017 The PHP Documentation Group

Licensed under the Creative Commons Attribution License v3.0 or later.

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