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This article mainly introduces what php can achieve random functions, the article is very detailed, has a certain reference value, interested friends must read it!

Php to achieve random functions are: 1, rand (), can generate random integers; 2, mt_rand (); 3, array_rand (), can return a random key name in the array; 4, shuffle (), can randomly disturb the array; 5, str_shuffle (); 6, uniqid ().

Operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

PHP random functions are mainly rand, mt_rand, array_rand, as well as random "arrangement" (disordered) functions shuffle, str_shuffle, can produce a unique ID uniqid.

1. Rand generates random numbers.

The rand () function uses libc's random number generator to generate random numbers, which is generally slow and uncertain, so it is recommended to use the mt_rand function instead.

The getrandmax () function returns the maximum random number that the rand function can produce (my system is 32767), so don't overshoot the return value of getrandmax when setting the second parameter of the rand function.

2. Mt_rand generates random numbers.

Many old libc random number generators have some uncertain and unknown characteristics and are very slow. The rand () function of PHP uses the libc random number generator by default. The mt_rand () function is used informally to replace it. This function uses the properties known in »Mersenne Twister as the random number generator, which can generate random values at an average speed of four times faster than the rand () provided by libc. It is strongly recommended that you use the mt_rand function instead of rand during development.

Returns a pseudorandom number between 0 and mt_getrandmax () if the optional arguments min and max,mt_rand () are not provided. For example, if you want a random number between 3 and 20, including 3 and 20, use mt_rand (3,20).

3. Array_rand function

Array_rand returns random key values in the array, a bit like the mt_rand () function, and the rest is nothing special, just flexible.

4. Shuffle function

Shuffle function is to disrupt the sequence of an array, a little random meaning, here is put in the random function. The return value is a Bool value, which is equivalent to a direct reference to the original variable.

5. Str_shuffle function

Here, the function of str_shuffle is similar to that of shuffle, except that the return value is the original string of str_shuffle.

6. Uniqid function

Uniqid can produce unique strings, and this application can be quite extensive.

These are all the contents of the article "what are the random functions that can be implemented by php?" Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!

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