Random\Randomizer::pickArrayKeys

(PHP 8 >= 8.2.0)

Random\Randomizer::pickArrayKeys — Select random array keys

说明

public Random\Randomizer::pickArrayKeys(array $array, int $num): array

Uniformly selects num distinct array keys of the input array.

Each key of the input array is equally likely to be returned.

警告

The selection of the array keys depends on the internal structure of the input array. The returned array keys might be different for two equal input arrays and two Random\Engines with identical state, depending on how the input arrays have been created.

参数

array

The array whose array keys are selected.

num

The number of array keys to return; must be between 1 and the number of elements in array.

返回值

An array containing num distinct array keys of array.

The returned array will be a list (array_is_list()). It will be a subset of the array returned by array_keys().

错误／异常

示例

示例 #1 Random\Randomizer::pickArrayKeys() example

<?php
$r = new \Random\Randomizer();

$fruits = [ 'red' => '🍎', 'green' => '🥝', 'yellow' => '🍌', 'pink' => '🍑', 'purple' => '🍇' ];

// Pick 2 random array keys:
echo "Keys: ", implode(', ', $r->pickArrayKeys($fruits, 2)), "\n";

// Pick another 3:
echo "Keys: ", implode(', ', $r->pickArrayKeys($fruits, 3)), "\n";
?>

以上示例的输出类似于：

Keys: yellow, purple
Keys: red, green, yellow

示例 #2 Picking random values

<?php
$r = new \Random\Randomizer();

$fruits = [ 'red' => '🍎', 'green' => '🥝', 'yellow' => '🍌', 'pink' => '🍑', 'purple' => '🍇' ];

$keys = $r->pickArrayKeys($fruits, 2);
// Look up the values for the picked keys.
$selection = array_map(
static fn ($key) => $fruits[$key],
$keys
);

echo "Values: ", implode(', ', $selection), "\n";
?>

以上示例的输出类似于：

Values: 🍎, 🍇

参见

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