从阵列中的特定位置返回最后的值 [英] Return last values from specific position in array
问题描述
有页面阵列,
$pages = array(
1,
2,
3,
...
100,
101
);
和有一个变量 $ CURRENT_PAGE
。所有我想要做的就是类似Digg的风格分页,这样它看起来像这样,
And there's a variable $current_page
. All I'm trying to do is pagination in digg-like style, so that it would look like this,
< 4 5 6 7 .... 15 16 17 18 >
,想到的第一件事是从特定的立场,即等于 $ CURRENT_PAGE
获得最后和previous数组值。
The first thing that comes to mind is to get last and previous array values from specific position that equals to $current_page
.
于是我开始一个基本的为
循环,但问题是页面的数量可能会非常大,所以我不认为这是做一个有效的事情。有没有这样做的另一种适当的方式? (也许通过本机阵列_ *
函数)?
So I started with a basic for
loop, but the problem is that amount of pages could be very large, so I don't think that's an efficient thing to do. Is there any another proper way of doing this? (maybe via native array_*
functions)?
推荐答案
下面的函数计算器建立像分页。其目标是:
The following function builds StackOverflow like pagination. The objectives are:
- 第一次和最后的链接必须是可见的总是
- previous和下一环节必须是可见的总是
- 在最前4链接/后当前页面应该是可见
而下面的功能显示完整的寻呼机,我们在如何计算周围的页面主要兴趣是一个和乙为当前页面的函数 传呼机大小和页计数
While the following function displays the complete pager, we are primarily interested in how to calculate the surrounding pages a and b as a function of current page, pager size and page count.
function so_like_pager($current_page, $page_count, $pager_size = 4) {
if ($current_page <= $pager_size) {
// the pager for first 4 pages starts from 1
$a = 1;
$b = min(1 + $pager_size, $page_count);
} else {
// the pager for remaining pages ends at current page + 2
// and starts so that 4 links are shown
$b = min($current_page + ($pager_size >> 1), $page_count);
$a = $b - $pager_size;
}
// return array("show_from" => $a, "show_upto" => $b);
echo '<p>';
if ($current_page !== 1) {
echo '<a href="' . so_like_pager_page(1) . '">' . 1 . '</a> ';
} else {
echo '<b>' . 1 . '</b> ';
}
if ($a > 1 + 1) {
echo '<span>...</span> ';
}
for ($i = $a; $i <= $b; $i++) {
if ($i !== 1 && $i !== $page_count) {
if ($current_page !== $i) {
echo '<a href="' . so_like_pager_page($i) . '">' . $i . '</a> ';
} else {
echo '<b>' . $i . '</b> ';
}
}
}
if ($b < $page_count - 1) {
echo '<span>...</span> ';
}
if ($current_page !== $page_count) {
echo '<a href="' . so_like_pager_page($page_count) . '">' . $page_count . '</a> ';
} else {
echo '<b>' . $page_count . '</b> ';
}
echo '</p>';
}
function so_like_pager_page($page) {
return 'page-' . $page . '/';
}
测试:
so_like_pager(1, 100);
so_like_pager(2, 100);
so_like_pager(3, 100);
so_like_pager(4, 100);
so_like_pager(5, 100);
so_like_pager(6, 100);
so_like_pager(50, 100);
so_like_pager(99, 100);
so_like_pager(100, 100);
输出:
PS:注意:我从ASP经典急于PHP移植此功能并没有测试对边界情况
PS: Note: I ported this function from ASP classic to PHP in a hurry and did not test against edge cases.
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