显示和随机化PHP数组

Question

我有一个数组显示如下结果：

Array 
(
    [0] => 71 
    [1] => 56 
    [2] => 64 
    [3] => 82 
    [4] => 90 
    [5] => 80 
    [6] => 65 
    [7] => 62 
    [8] => 14 
    [9] => 3 
) 

我的代码是：

while($row = mysql_fetch_assoc($result)) 
{ 

    $show[] = $row['number']; 

} 
    echo '<pre>'; print_r($show); 

如何可以随机数组内容，并显示它们作为5位数字仅Ë ：克

Answer 1

$rand5 = array_rand(array_flip($show), 5); 
// we need array_flip because array_rand returns the keys 

http://php.net/array_rand

http://php.net/array_flip

Answer 2

我将与shuffle去随机化阵列，每获得德数组的5个元素，这真的取决于你的需要，有什么事你到底想要完成，得到了第5种元素，最后一个或其他逻辑。

Answer 3

试试这个：

$arr=array(); 
for ($i=0;$i<5;$i++) 
{ 
$arr[i]=$items[array_rand($items)]; 
} 

$arr包含结果

Answer 4

就应该得到这个查询不知道，但您也可能会使用

SELECT number 
FROM SomeTable 
ORDER BY RAND() 
LIMIT 5 

但是请注意，ORDER BY RAND （）效率很低，因此只适用于处理少量行的情况。但是，如果您要带回大量的行，那么在PHP中执行操作也是低效的。

还有一种更有效的方法可以返回一个随机行，所以如果你有很多行，可能值得高效地检索单行5次并将结果联合在一起（尽管你需要考虑的可能性，随机行可能是重复的

例如（而不是真正与这个幸福）： - 。

(SELECT r1.number 
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND() * (MAX(number) - MIN(number)) + MIN(number) AS number 
    FROM SomeTable 
) AS r2 
ON r1.number >= r2.number 
ORDER BY r1.number ASC 
LIMIT 1) 
UNION 
(SELECT r1.number 
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND() * (MAX(number) - MIN(number)) + MIN(number) AS number 
    FROM SomeTable 
) AS r2 
ON r1.number >= r2.number 
ORDER BY r1.number ASC 
LIMIT 1) 
UNION 
(SELECT r1.number 
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND() * (MAX(number) - MIN(number)) + MIN(number) AS number 
    FROM SomeTable 
) AS r2 
ON r1.number >= r2.number 
ORDER BY r1.number ASC 
LIMIT 1) 
UNION 
(SELECT r1.number 
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND() * (MAX(number) - MIN(number)) + MIN(number) AS number 
    FROM SomeTable 
) AS r2 
ON r1.number >= r2.number 
ORDER BY r1.number ASC 
LIMIT 1) 
UNION 
(SELECT r1.number 
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND() * (MAX(number) - MIN(number)) + MIN(number) AS number 
    FROM SomeTable 
) AS r2 
ON r1.number >= r2.number 
ORDER BY r1.number ASC 
LIMIT 1) 
UNION 
(SELECT r1.number 
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND() * (MAX(number) - MIN(number)) + MIN(number) AS number 
    FROM SomeTable 
) AS r2 
ON r1.number >= r2.number 
ORDER BY r1.number ASC 
LIMIT 1) 
UNION 
(SELECT r1.number 
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND() * (MAX(number) - MIN(number)) + MIN(number) AS number 
    FROM SomeTable 
) AS r2 
ON r1.number >= r2.number 
ORDER BY r1.number ASC 
LIMIT 1) 
UNION 
(SELECT r1.number 
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND() * (MAX(number) - MIN(number)) + MIN(number) AS number 
    FROM SomeTable 
) AS r2 
ON r1.number >= r2.number 
ORDER BY r1.number ASC 
LIMIT 1) 
UNION 
(SELECT r1.number 
FROM SomeTable AS r1 
INNER JOIN 
(
    SELECT RAND() * (MAX(number) - MIN(number)) + MIN(number) AS number 
    FROM SomeTable 
) AS r2 
ON r1.number >= r2.number 
ORDER BY r1.number ASC 
LIMIT 1) 
LIMIT 5 

SQL小提琴的位置： -

http://sqlfiddle.com/#!2/14caa/4

这是获得10个随机行，然后使用进一步限制5只得到5行。当然，这可能不会得到5行（不太可能，但可能每个联合查询都会返回同一行）的可能性很小。