How to output different values from an array - php

Question

I have a problem with my code. what I want to do is to delete an item from the array when it has been called meaning that, I want every output to be different. I want to use it to rotate proxy and there are over 150 proxies in the array. Here's an example of my code.
for ( $i = 1; $i < 2; $i++ )
{
// If the array_history is empty, re-populate it.
if (empty($array_history))
$array_history = $array;
// Select a random key.
$key = array_rand($array_history, 1);
// Save the record in $selected.
$selected = $array_history[$key];
// Remove the key/pair from the array.
unset($array_history[$key]);
// Echo the selected value.
echo $selected;
}
How can I do this or is a for loop not suitable for this? thanks in advance.

Answer 1

What you want to do is spread access over 150 proxies. In this case, it is not really necessary to do it randomly. You can just go through the array.
<?php
$array = [0, 1, 2, 3, 4, 5, 6];
for ( $i = 1; $i < 20; $i++ )
{
echo getNext($array) . '<br>';
}
function getNext (&$array) {
$e = next($array); // Every time next element is selected. Each output is different.
if ($e)
return $e;
else
return reset($array);
}
?>

Answer 2

This seems like a good application for a generator. This one takes an array of proxy addresses and loops over the array in random order, shuffling the array each time it starts the loop again.
function get_proxy($proxies) {
$i = 0;
$len = count($proxies);
while (true) {
if ($i == 0) shuffle($proxies);
yield $proxies[$i];
$i = ($i + 1) % $len;
}
}
To use this, you would do something like this:
$proxies = array('10.0.0.4', '192.168.0.1', '10.1.0.1');
$i = 0;
foreach (get_proxy($proxies) as $proxy) {
echo "$proxy\n";
$i++;
// stop otherwise infinite loop
if ($i == 9) break;
}
Note that since the generator has an infinite loop in it, the external foreach loop will also be infinite, and so needs a way to break out (I've used a simple counter in this case).
Sample output for the above code:
10.1.0.1
10.0.0.4
192.168.0.1
192.168.0.1
10.1.0.1
10.0.0.4
10.1.0.1
192.168.0.1
10.0.0.4
Demo on 3v4l.org
If a generator doesn't suit your code structure, you could use a function with static variables to return a new proxy on each call:
$proxies = array('10.0.0.4', '192.168.0.1', '10.1.0.1');
function get_proxy($proxies) {
static $i = 0, $keys;
if (!isset($keys)) $keys = array_keys($proxies);
if ($i == 0) shuffle($keys);
$proxy = $proxies[$keys[$i]];
$i = ($i + 1) % count($keys);
return $proxy;
}
for ($i= 0; $i < 9; $i++) {
echo get_proxy($proxies) . "\n";
}
Sample output for this code:
10.1.0.1
10.0.0.4
192.168.0.1
192.168.0.1
10.1.0.1
10.0.0.4
10.0.0.4
192.168.0.1
10.1.0.1
Demo on 3v4l.org

Answer 3

When you define an array in php such as
<?php
$alphabet = array(a, b, c)
?>
Your trying to look for the elements in the array. The element list always starts at a count of 0. So to call individual elements count from left to right starting at 0.
<?php
#a
echo $alphabet[0];
#b
echo $alphabet[1];
#c
echo $alphabet[2];
?>
The above section should yield a result of abc because there are no breaks.
For loops are really handy for going through the entire array and running checks, error analysis or even math as examples.

Answer 4

I've changed tho cede slightly, to me it reads as code that will take a selection of items, pick one at random, discard the item, and then pick again until none are left. If there are none left, copy the original array and start again.
Currently your code loops once. I've extended the loop to 4 iteratons here. And upon each random selection, am storing that random key in a history array. You can then refer to that history later in your code.
<?php
$array =
[
'beatle' => 'John',
'stone' => 'Mick',
'floyd' => 'Syd'
];
for ($history = [], $i = 1; $i < 5; $i++)
{
if (empty($buffer))
$buffer = $array;
$key = array_rand($buffer, 1);
$history[] = $key;
echo $buffer[$key], "\n";
unset($buffer[$key]);
}
var_export($history);
Example output:
Syd
Mick
John
Syd
array (
0 => 'floyd',
1 => 'stone',
2 => 'beatle',
3 => 'floyd',
)
Referring to the history array above:
echo $array[$history[3]];
Would output Syd.
Adapting and encapsulating the above in a class. This will do the same (but not store the history of picks), taking an item from an array at random and remove until there are no more items in the array, and then replenish the list and so on:
class RandomProxies
{
const PROXIES =
[
'proxy1' => 'foo.example.com',
'proxy2' => 'bar.example.com',
'proxy3' => 'baz.example.com',
];
private $buffer;
public function getProxy() {
if (empty($this->buffer))
$this->buffer = self::PROXIES;
$key = array_rand($this->buffer);
$proxy = self::PROXIES[$key];
unset($this->buffer[$key]);
return $proxy;
}
}
$randomiser = new RandomProxies;
foreach(range(1,4) as $n) {
echo $randomiser->getProxy(), "\n";
}
Example output:
foo.example.com
baz.example.com
bar.example.com
foo.example.com