PHP - Display a different string on refresh, but not random

Let's say I have this array:

array('A', 'B', 'C', 'D');

I want to display one item at a time, on page reload. For example, on first visit, it shows 'A'; on refresh, it shows 'B'; then 'C'; then 'D'; then 'A'. The point is to show these item in order on each page reload开发者_JS百科. I think I should use cookies, but I don't have the knowledge.

I don't want to do this with random because it will show something like 'C' then 'A' then 'D'...

Can you help me with some tips, hints or keywords to search? I don't know how to start.

Any help is appreciated!

You have to store what the last request showed and return the element base on this. You can use a file or a database for this. If you just want to go through on each request, you could store a file and increment a counter between 0 and 3, read the element from the array and safe the counter.

If you want to make it for every user, you could set a cookie and increment the counter there. Or you try to identify the user (again, cookie or session) and increment the counter in a database, which might be some overhead.

You could use sessions as in

<?
session_start();
$data = array('A', 'B', 'C', 'D');
if (isset($_SESSION['last_index'])) {
  $_SESSION['last_index'] = ($_SESSION['last_index'] + 1) % count($data);
} else {
  $_SESSION['last_index'] = 0;
}
echo $data[$_SESSION['last_index']];

Read about sessions

You can do this with a PHP session.

<?php
$default = Array('A', 'B', 'C', 'D') ;
session_start() ;
$_SESSION['myarray'] = isset($_SESSION['myarray']) ? $_SESSION['myarray'] : $default ;
$_SESSION['myarray'] = (count($_SESSION['myarray']) > 0) ? $_SESSION['myarray'] : $default ;
echo array_pop($_SESSION['myarray']) ;
?>

Use array_rand (http://php.net/array_rand) and array_pop. Store the array in the session:

if ( !isset( $_SESSION['strings'] ) or !count( $_SESSION['strings'] ) ) {
    // initialize the array (in random order)
    $_SESSION['strings'] = array_rand( array('A', 'B', 'C', 'D') );
}

$item = array_pop( $_SESSION['strings'] ); // take one element off the array

The above regenerates the array everytime all the items have been returned - if you want to maintain the same order for the entire session, do:

if ( !isset( $_SESSION['strings'] ) ) {
    // initialize the array (in random order)
    $_SESSION['strings'] = $_SESSION['strings_def'] = array_rand( array('A', 'B', 'C', 'D') );
}

if ( !count( $_SESSION['strings'] ) ) {
    $_SESSION['strings'] = $_SESSION['strings_def'];
}

$item = array_pop( $_SESSION['strings'] ); // take one element off the array

$strings = array('A','B','C','D');
$cur_index = (empty($_SESSION['page_idx']))?$_SESSION['page_idx']:-1;
++$cur_index;
if ($cur_index>=count($strings))
    $cur_index = 0;
echo $strings[$cur_index];
//And finally, the trick itself
$_SESSION['page_idx'] = $cur_index;

<?php
session_start();
$arr = array('A','B','C','D');
if (!isset($_SESSION['idx'])) $_SESSION['idx'] = 0;
else $_SESSION['idx'] = (($_SESSION['idx'] > (count($arr)-2)) ? 0 :  ($_SESSION['idx']+1) );
echo $arr[$_SESSION['idx']];
?>