blocks|key|1420262|text|您也可以只执行以下操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1420263|$k+=+array_rand($array);
$v+=+$array[$k];|code-block|syntax|javascript|1420264|当你有一个关联数组时，这就是这样做的方法。|1420265|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You can also do just:

<pre><code>$k = array_rand($array);
$v = $array[$k];
</code></pre>

This is the way to do it when you have an associative array.

blocks|key|1205188|text|PHP为此提供了一个函数:+array_rand()|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1205189|http://php.net/manual/en/function.array-rand.php|offset|length|1205190|$ran+=+array(1,2,3,4);
$randomElement+=+$ran[array_rand($ran,+1)];|code-block|syntax|javascript|1205191|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|1C|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@$D|T|E|U|1|V]]|A|$]]|$1|F|3|G|5|H|7|W|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|C]]]]

PHP provides a function just for that: array_rand() 
<a href="http://php.net/manual/en/function.array-rand.php" rel="noreferrer">http://php.net/manual/en/function.array-rand.php</a>

<pre><code>$ran = array(1,2,3,4);
$randomElement = $ran[array_rand($ran, 1)];
</code></pre>

blocks|key|1205114|text|您可以使用mt_rand()|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1205115|$random+=+$ran[mt_rand(0,+count($ran)+-+1)];|code-block|syntax|javascript|1205116|如果您需要值，这也可以作为一个函数来使用|1205117|function+random_value($array,+$default=null)
{
++++$k+=+mt_rand(0,+count($array)+-+1);
++++return+isset($array[$k])?+$array[$k]:+$default;
}|1205118|entityMap|0|LINK|mutability|MUTABLE|url|http://is.php.net/manual/en/function.mt-rand.php^0|5|9|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

You can use <a href="http://is.php.net/manual/en/function.mt-rand.php" rel="noreferrer">mt_rand()</a>

<pre><code>$random = $ran[mt_rand(0, count($ran) - 1)];
</code></pre>

This comes in handy as a function as well if you need the value

<pre><code>function random_value($array, $default=null)
{
 $k = mt_rand(0, count($array) - 1);
 return isset($array[$k])? $array[$k]: $default;
}
</code></pre>

blocks|key|1205319|text|$value+=+$array[array_rand($array)];|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1205320|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>$value = $array[array_rand($array)];
</code></pre>

blocks|key|1420322|text|array_rand函数在大型数组上的分布似乎不均匀，并不是每个数组项都同样有可能被选中。在数组上使用shuffle，然后获取第一个元素就没有这个问题：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1420323|$myArray+=+array(1,+2,+3,+4,+5);

//+Random+shuffle
shuffle($myArray);

//+First+element+is+random+now
$randomValue+=+$myArray[0];|code-block|syntax|javascript|1420324|entityMap|0|LINK|mutability|MUTABLE|url|http://www.php.net/manual/en/function.shuffle.php^0|0|A|1F|7|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@$9|V|A|W|1|X]]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

The <code>array_rand</code> function seems to have an uneven distribution on large arrays, not every array item is equally likely to get picked. Using <a href="http://www.php.net/manual/en/function.shuffle.php" rel="noreferrer">shuffle</a> on the array and then taking the first element doesn't have this problem:

<pre><code>$myArray = array(1, 2, 3, 4, 5);

// Random shuffle
shuffle($myArray);

// First element is random now
$randomValue = $myArray[0];
</code></pre>

blocks|key|1420200|text|$rand+=+rand(1,4);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1420201|或者，具体来说，对于数组：|unstyled|1420202|$array+=+array('a+value',+'another+value',+'just+some+value',+'not+some+value');
$rand+=+$array[+rand(0,+count($array)-1)+];|1420203|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>$rand = rand(1,4);
</code></pre>

or, for arrays specifically:

<pre><code>$array = array('a value', 'another value', 'just some value', 'not some value');
$rand = $array[ rand(0, count($array)-1) ];
</code></pre>

blocks|key|1420655|text|在我的例子中，我必须获取两个对象的值。我分享这个简单的解决方案。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1420656|$ran+=+array("a","b","c","d");
$ranval+=+array_map(function($i)+use($ran){return+$ran[$i];},array_rand($ran,2));|code-block|syntax|javascript|1420657|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

In my case, I have to get 2 values what are objects. I share this simple solution.

<pre><code>$ran = array("a","b","c","d");
$ranval = array_map(function($i) use($ran){return $ran[$i];},array_rand($ran,2));
</code></pre>

blocks|key|1420516|text|一行：$ran[rand(0,+count($ran)+-+1)]|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1420517|entityMap^0|3|U|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

One line: <code>$ran[rand(0, count($ran) - 1)]</code>

blocks|key|1205682|text|我需要一个短数组的单行版本：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1205683|($array+=+[1,+2,+3,+4])[mt_rand(0,+count($array)+-+1)]|code-block|syntax|javascript|1205684|或者如果数组是固定的：|1205685|[1,+2,+3,+4][mt_rand(0,+3]|1205686|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

I needed one line version for short array:

<pre><code>($array = [1, 2, 3, 4])[mt_rand(0, count($array) - 1)]
</code></pre>

or if array is fixed:

<pre><code>[1, 2, 3, 4][mt_rand(0, 3]
</code></pre>

blocks|key|1420729|text|在线：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1420730|echo+$array[array_rand($array,1)]|code-block|syntax|javascript|1420731|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

On-liner:

<pre><code>echo $array[array_rand($array,1)]
</code></pre>

blocks|key|1420432|text|您的选择是否有任何安全隐患？如果是，请使用random_int()和array_keys()。(random_bytes()仅适用于PHP7，但有一个polyfill+for+PHP+5)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1420433|function+random_index(array+$source)
{
++++$max+=+count($source)+-+1;
++++$r+=+random_int(0,+$max);
++++$k+=+array_keys($source);
++++return+$k[$r];
}|code-block|syntax|javascript|1420434|用法：|1420435|$array+=+[
++++'apple'+=>+++1234,
++++'boy'+++=>+++2345,
++++'cat'+++=>+++3456,
++++'dog'+++=>+++4567,
++++'echo'++=>+++5678,
++++'fortune'+=>+6789
];
$i+=+random_index($array);
var_dump([$i,+$array[$i]]);|1420436|演示：https://3v4l.org/1joB1|1420437|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/paragonie/random_compat|1|https://3v4l.org/1joB1^0|L|C|Y|C|1C|E|23|I|0|0|0|0|0|3|M|1|0^^$0|@$1|2|3|4|5|6|7|10|8|@$9|11|A|12|B|C]|$9|13|A|14|B|C]|$9|15|A|16|B|C]]|D|@$9|17|A|18|1|19]]|E|$]]|$1|F|3|G|5|H|7|1A|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1B|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|1C|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1D|8|@]|D|@$9|1E|A|1F|1|1G]]|E|$]]|$1|Q|3|-4|5|6|7|1H|8|@]|D|@]|E|$]]]|R|$S|$5|T|U|V|E|$W|X]]|Y|$5|T|U|V|E|$W|Z]]]]

Does your selection have any security implications? If so, use <code>random_int()</code> and <code>array_keys()</code>. (<code>random_bytes()</code> is PHP 7 only, but there is a <a href="https://github.com/paragonie/random_compat" rel="nofollow">polyfill for PHP 5</a>).

<pre><code>function random_index(array $source)
{
 $max = count($source) - 1;
 $r = random_int(0, $max);
 $k = array_keys($source);
 return $k[$r];
}
</code></pre>

Usage:

<pre><code>$array = [
 'apple' =&gt; 1234,
 'boy' =&gt; 2345,
 'cat' =&gt; 3456,
 'dog' =&gt; 4567,
 'echo' =&gt; 5678,
 'fortune' =&gt; 6789
];
$i = random_index($array);
var_dump([$i, $array[$i]]);
</code></pre>

Demo: <a href="https://3v4l.org/1joB1" rel="nofollow">https://3v4l.org/1joB1</a>

blocks|key|1420465|text|使用rand()获取随机数以回显随机密钥。在示例中:0-3|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1420466|$ran+=+array(1,2,3,4);
echo+$ran[rand(0,3)];|code-block|syntax|javascript|1420467|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Use rand() to get random number to echo random key. In ex: 0 - 3

<pre><code>$ran = array(1,2,3,4);
echo $ran[rand(0,3)];
</code></pre>

blocks|key|1205611|text|这将很好地与内联数组一起工作。另外，我认为当包装在一个函数中时，事情会更整洁，更容易重用。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1205612|function+array_rand_value($a)+{
++++return+$a[array_rand($a)];
}|code-block|syntax|javascript|1205613|用法：|1205614|array_rand_value(array("a",+"b",+"c",+"d"));|1205615|在小于7.1.0的PHP上，array_rand()使用rand()，因此您不希望在任何与安全性或密码学相关的事情上使用此函数。在PHP+7.1.0%2B上，使用这个函数不用担心，因为rand()+has+been+aliased+to+mt_rand()。|offset|length|style|CODE|1205616|entityMap|0|LINK|mutability|MUTABLE|url|https://php.net/manual/en/migration71.incompatible.php#migration71.incompatible.rand-srand-aliases^0|0|0|0|0|E|C|S|6|2I|6|39|9|2I|10|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|10|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|12|8|@$M|13|N|14|O|P]|$M|15|N|16|O|P]|$M|17|N|18|O|P]|$M|19|N|1A|O|P]]|9|@$M|1B|N|1C|1|1D]]|A|$]]|$1|Q|3|-4|5|6|7|1E|8|@]|9|@]|A|$]]]|R|$S|$5|T|U|V|A|$W|X]]]]

This will work nicely with in-line arrays. Plus, I think things are tidier and more reusable when wrapped up in a function.

<pre><code>function array_rand_value($a) {
 return $a[array_rand($a)];
}
</code></pre>

Usage:

<pre><code>array_rand_value(array("a", "b", "c", "d"));
</code></pre>

On PHP &lt; 7.1.0, <code>array_rand()</code> uses <code>rand()</code>, so you wouldn't want to this function for anything related to security or cryptography. On PHP 7.1.0+, use this function without concern since <a href="https://php.net/manual/en/migration71.incompatible.php#migration71.incompatible.rand-srand-aliases" rel="nofollow noreferrer"><code>rand()</code> has been aliased to <code>mt_rand()</code></a>.

blocks|key|1205391|text|我的答案基于@ÓlafurWaage的函数。我试图使用它，但当我试图修改返回对象时，遇到了引用问题。我更新了他的函数，通过引用传递和返回。新功能是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1205392|function+&random_value(&$array,+$default=null)
{
++++$k+=+mt_rand(0,+count($array)+-+1);
++++if+(isset($array[$k]))+{
++++++++return+$array[$k];
++++}+else+{
++++++++return+$default;
++++}
}|code-block|syntax|javascript|1205393|有关更多上下文，请参阅Passing/Returning+references+to+object+%2B+changing+object+is+not+working上的我的问题|offset|length|1205394|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/32702536/passing-returning-references-to-object-changing-object-is-not-working^0|0|0|B|1Z|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

I'm basing my answer off of @ÓlafurWaage's function. I tried to use it but was running into reference issues when I had tried to modify the return object. I updated his function to pass and return by reference. The new function is:

<pre><code>function &amp;random_value(&amp;$array, $default=null)
{
 $k = mt_rand(0, count($array) - 1);
 if (isset($array[$k])) {
 return $array[$k];
 } else {
 return $default;
 }
}
</code></pre>

For more context, see my question over at <a href="https://stackoverflow.com/questions/32702536/passing-returning-references-to-object-changing-object-is-not-working">Passing/Returning references to object + changing object is not working</a>

blocks|key|1420757|text|从数组中获取随机值。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1420758|function+random($array)
{
++++///+Determine+array+is+associative+or+not
++++$keys+=+array_keys($array);
++++$givenArrIsAssoc+=+array_keys($keys)+!==+$keys;

++++///+if+array+is+not+associative+then+return+random+element
++++if(!$givenArrIsAssoc){
++++++++return+$array[array_rand($array)];
++++}

++++///+If+array+is+associative+then+
++++$keys+=+array_rand($array,+$number);
++++$results+=+[];
++++foreach+((array)+$keys+as+$key)+{
++++++++$results[]+=+$array[$key];
++++}
++++return+$results;
}|code-block|syntax|javascript|1420759|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Get random values from an array.
<pre><code>function random($array)
{
 /// Determine array is associative or not
 $keys = array_keys($array);
 $givenArrIsAssoc = array_keys($keys) !== $keys;

 /// if array is not associative then return random element
 if(!$givenArrIsAssoc){
 return $array[array_rand($array)];
 }

 /// If array is associative then 
 $keys = array_rand($array, $number);
 $results = [];
 foreach ((array) $keys as $key) {
 $results[] = $array[$key];
 }
 return $results;
}
</code></pre>

blocks|key|1205157|text|您可以从数组中获得一个随机数，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1205158|$randomValue+=+$rand[array_rand($rand,1)];|code-block|syntax|javascript|1205159|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You get a random number out of an array as follows:

<pre><code>$randomValue = $rand[array_rand($rand,1)];
</code></pre>

I have an array called <code>$ran = array(1,2,3,4);</code>

I need to get a random value out of this array and store it in a variable, how can I do this?

How to get random value out of an array?

我有一个名为$ran = array(1,2,3,4);的数组我需要从这个数组中获取一个随机值，并将其存储在一个变量中，我该怎么做呢？

问如何从数组中获取随机值？
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回答 16

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问如何从数组中获取随机值？
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