# rand

(PHP 4, PHP 5, PHP 7, PHP 8)

rand — Generate a random integer

### Descripción

rand(): int
rand(int `$min`, int `$max`): int

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)`.

Precaución

Esta función no genera valores criptográficos fiables por lo que no debería empelarse para propósitos criptográficos. Si fuera necesario un valor criptográfico seguro, considérese utilizar random_int(), random_bytes(), o openssl_random_pseudo_bytes() en su lugar.

> Nota: 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.

> Nota: 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().

### Parámetros

`min`

  The lowest value to return (default: 0)

`max`

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

### Valores devueltos

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

### Historial de cambios

Versión | Descripción
--- | ---
7.2.0 | rand() has received a bug fix for a modulo bias bug. This means that sequences generated with a specific seed may differ from PHP 7.1 on 64-bit machines.
7.1.0 | rand() has been made an alias of mt_rand().

### Ejemplos

Ejemplo #1 rand() example

`<?php
echo rand(), "\n";
echo rand(), "\n";
echo rand(5, 15), "\n";
?>`

El resultado del ejemplo sería algo similar a:

    7771
    22264
    11

### Notas

Advertencia

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

### Ver también

- 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() - Get a cryptographically secure, uniformly selected integer
- random_bytes() - Get cryptographically secure random bytes