在 PHP 中获取随机布尔值 true/false

在 PHP 中获得随机布尔值 true/false 的最优雅的方法是什么?

我能想到的是:

$value = (bool)rand(0,1);

但是将整数转换为布尔值会带来什么缺点吗?

或者这是一种“正式”的做法?

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If you don't wish to have a boolean cast (not that there's anything wrong with that) you can easily make it a boolean like this:

$value = rand(0,1) == 1;

Basically, if the random value is 1, yield true, otherwise false. Of course, a value of 0 or 1 already acts as a boolean value; so this:

if (rand(0, 1)) { ... }

Is a perfectly valid condition and will work as expected.

Alternatively, you can use mt_rand() for the random number generation (it's an improvement over rand()). You could even go as far as openssl_random_pseudo_bytes() with this code:

$value = ord(openssl_random_pseudo_bytes(1)) >= 0x80;

Update

In PHP 7.0 you will be able to use random_int(), which generates cryptographically secure pseudo-random integers:

$value = (bool)random_int(0, 1);

I use a simply

rand(0,1) < 0.5

Just for completeness, if you want to use it in an if condition, there is no need to cast, since 0 is considered false and mt_rand produces random integers in the range:

if (mt_rand(0,1)) { // 0 = false, 1 = true
// whatever
}

Note: mt_rand is 4x faster than rand

The mt_rand() function is a drop-in replacement for the older rand(). It uses a random number generator with known characteristics using the "Mersenne Twister", which will produce random numbers four times faster than what the average libc rand() provides. (Source: https://www.php.net/manual/en/function.mt-rand.php)

php stan recomended

1 === random_int(0, 1)