Summary of five methods for generating non-repeated random numbers in PHP

Random numbers are useful for Web applications, WAP or mobile applications. I often need to deal with random numbers or random arrays in a few small projects recently. Therefore, I would like to summarize several common methods for generating non-repeated random numbers in PHP.

Random numbers are useful for Web applications, WAP or mobile applications. I often need to deal with random numbers or random arrays in a few small projects recently. Therefore, I would like to summarize several common methods for generating non-repeated random numbers in PHP.

Method 1:

$ Numbers = range (1, 50 );

// Shuffle will immediately disrupt the array order

Shuffle ($ numbers );

// Array_slice retrieves a segment of the array

$ Num = 6;

$ Result = array_slice ($ numbers, 0, $ num );

Print_r ($ result );

?>

Method 2:

$ Numbers = range (1, 20 );

// Broadcast the seed of the random number generator, which is dispensable and does not affect the test result.

Srand (float) microtime () * 1000000 );

Shuffle ($ numbers );

// Skip the first value of the list (the index is saved)

While (list (, $ number) = each ($ numbers )){

Echo "$ number ";

}

?>

Method 3:

Function NoRand ($ begin = 0, $ end = 20, $ limit = 5 ){

$ Rand_array = range ($ begin, $ end );

Shuffle ($ rand_array); // call the random array arrangement function.

Return array_slice ($ rand_array, 0, $ limit); // The first $ limit

}

Print_r (NoRand ());

?>

Five distinct values can be randomly generated between 1 and 20.

Method 4:

The code is as follows:

$ Tmp = array ();

While (count ($ tmp) <5 ){

$ Tmp [] = mt_rand (1, 20 );

$ Tmp = array_unique ($ tmp );

}

Print_r ($ tmp );

?>

Method 5:

The code is as follows:

$ Tmp = range (1, 30 );

Print_r (array_rand ($ tmp, 10 ));

?>

This may be simpler (ps: If the step is specified in the range, you must note whether the second parameter of array_rand exceeds the length of $ tmp ).