PHP, generate previous and next links from array with numbers - php

Question

I have an array like this:
$pages = (1, 29, 209, 389, 440, 527)
And I want to make simple HTML navigation through these pages. Only 'first', 'last', 'prev' and 'next' links.
And when I click the 'next'/'prev' link they had to change accordingly.
E.g. when I am at page 389 prev and next to be 209 and 440. If I am at page 440 prev and next to be 389 and 527.

Answer 1

Here is one simple approach:
$pages = array(1, 29, 209, 389, 440, 527);
$current = isset($_GET['page']) ? $_GET['page'] : $pages[0];
// current page
$key = array_search($current, $pages);
echo 'current page: ' . $pages[$key] . '<br />';
// previous page
$prev = $key - 1;
if ($prev >= 0 && $prev < count($pages)) {
echo 'prev | ';
} else {
echo 'prev | ';
}
// next page
$next = $key + 1;
if ($next >= 0 && $next < count($pages)) {
echo 'next';
} else {
echo 'next';
}
Assuming the keys will always be in order, then the first page will always be at $pages[0], and to get the last you could use $pages[key(array_slice($pages, -1, 1, true))]

Answer 2

function printPager($pageList,$currentPage)
{
$links="";
if(($currentIndex = array_search($currentPage, $pageList))!== NULL)
{
$links .=
//first
($currentIndex!=0?"<a href='/".($pageList[0])."'>First</a> ":"") .
//prev
(isset($pageList[$currentIndex-1])?"<a href='/".($pageList[$currentIndex-1])."'>Prev</a> ":"").
//next
(isset($pageList[$currentIndex+1])?"<a href='/".($pageList[$currentIndex+1])."'>Next</a> ":"").
//last
($currentIndex!=count($pageList)-1?"<a href='/".($pageList[count($pageList)-1])."'>Last</a>":"");
}
echo $links;
}
printPager(array(20,4,10,14),20);

Answer 3

try this:
<?php
$pages = array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
$active = 1;
$last = false;
$next = false;
if (isset($_GET['page']))
{
$active = $_GET['page'];
$last = $active - 1;
$next = $active + 1;
if (!in_array($next, $pages))
{
$next = false;
}
if (($last < 0) or !in_array($last, $pages))
{
$last = false;
}
}
?>
<ul>
<li>
<- LAST
</li>
<?php foreach ($pages as $page): ?>
<li><?= $page ?> <?= $page == $active ? ' is active!' : ''?></li>
<?php endforeach; ?>
<li>
NEXT ->
</li>
</ul>

Answer 4

<ul>
<?php
$pages = [1,4,89,100,121,224,443,527];
$thisPage = $_GET['page'];
foreach($pages as $key => $page){
if($thisPage == $page){
$thisPageKey = $key;
}
}
foreach($pages as $key => $page){
if($key==0){
echo '<li>first</li>';
}
if($key+1==count($pages)){
echo '<li>last</li>';
}
if(array_key_exists($thisPageKey-1, $pages) && $thisPage == $page){
echo '<li>prev</li>';
}
if(array_key_exists($thisPageKey+1, $pages) && $thisPage == $page){
echo '<li>next</li>';
}
}
?>
</ul>

Answer 5

You could try this
$pages=array(1, 29, 209, 389, 440, 527);
foreach ( $array_keys=array_keys($pages) as $array_keys) {
$pages_invert[ $pages[$array_keys] ]=$array_keys;
}
echo 'first ('.$pages[0].')';
echo ' | ';
if( $pages_invert[$_GET['page_id']]-1 >= 0 ) echo 'previous ('.$pages[$pages_invert[$_GET['page_id']]-1].') ';
else echo 'previous';
echo ' | ';
echo 'current ('.$_GET['page_id'].')';
echo ' | ';
if( $pages_invert[$_GET['page_id']]+1 <= 5 ) echo 'next ('.$pages[$pages_invert[$_GET['page_id']]+1].')';
else echo 'next';
echo ' | ';
echo 'last ('.$pages[count($pages)-1].')';
The foreach command makes inversion of your original array for jumps from current to previous and next array keys at $pages array.
To preview how the arrays looks, put this code:
any line arter your $pages array definition
<?
echo '<pre>';
print_r($pages);
echo '</pre>';
echo '<pre>';
print_r($pages_invert);
echo '</pre>';
?>
Please notice the minimum items in the $pages array is 3 items.