Selecting a random element from a PHP associative array

问题

I've got an associative array in PHP and want to select a random key/value pair out of it. Here's what I have so far:

Initialize.

$locations = array();

Loops through a SQL query and adds key/val pairs:

array_push($locations, "'$location_id' => '$location_name'");

Later on, I select a random index of the array:

$rand = array_rand($locations);

Rand is just a number. So locations[$rand] gives me something like:

'1' => 'Location 1'

OK great, an assoc array element. At this point, I do not know the key of this assoc array, so I've tried the following things:

foreach($locations[$rand] as $loc_id => $location_name) { 
    echo "$key : $value<br/>\n";
}

$loc_id, $location_name = each($locations[$rand]);

$location_name = $locations[key($rand)];

None of these 3 attempts work. They all throw errors like "Passed variable is not an array".

I'm sure there's some simple 1 liner that can pluck a random key/value pair from the array. Or my syntax is off. I'd really appreciate the help.

回答1:

$array = array('a' => 1, 'b' => 2);
$key = array_rand($array);
$value = $array[$key];

回答2:

array_rand() returns a key from the array, not a value. You can just use:

$location_name = $locations[$rand];

To get the location name.

Here's a full example: http://codepad.org/zR2YdMGN

Just click submit a few times, you'll see the random working.

回答3:

your push is wrong

$locations[$location_id] = $location_name;

it should be

so, there is nothing about selecting random element in your question.
always debug your code, just to see if you have proper data before using it

来源：https://stackoverflow.com/questions/7209127/selecting-a-random-element-from-a-php-associative-array

标签

php

random

associative-array