我有一个数组的行数，我需要按两个参数排序。我试图使用usort()函数来实现这一目标，但我遇到了一些麻烦。
这是我的代码：
if ($sort == 'rating-desc') usort($records, array('browse_model', 'cmp'));
private function cmp($a, $b) {
$ratingCmp = strcmp($b['rating'], $a['rating']);
if ($ratingCmp == 0) {
return strcmp($b['title'], $a['title']);
} else {
return $ratingCmp;
}
}
以下是print_r()之前数组的usort()结果：
Array
(
[0] => Array
(
[isbn] => 1847199488
[title] => CodeIgniter 1.7
[rating] => 3.5
)
[1] => Array
(
[isbn] => 059615593X
[title] => CSS Cookbook, 3rd Edition (Animal Guide)
[rating] => 3.5
)
[2] => Array
(
[isbn] => 0321637984
[title] => Essential Facebook Development: Build Successful Applications for the Facebook Platform
[rating] => 3.5
)
[3] => Array
(
[isbn] => 0980576857
[title] => jQuery: Novice to Ninja
[rating] => 4.5
)
[4] => Array
(
[isbn] => 0596157134
[title] => Learning PHP, MySQL, and JavaScript: A Step-By-Step Guide to Creating Dynamic Websites (Animal Guide)
[rating] => 4.5
)
)
以下是usort()之后的结果（按评分排序，但不按标题排序）：
Array
(
[0] => Array
(
[isbn] => 0980576857
[title] => jQuery: Novice to Ninja
[rating] => 4.5
)
[1] => Array
(
[isbn] => 0596157134
[title] => Learning PHP, MySQL, and JavaScript: A Step-By-Step Guide to Creating Dynamic Websites (Animal Guide)
[rating] => 4.5
)
[2] => Array
(
[isbn] => 0321637984
[title] => Essential Facebook Development: Build Successful Applications for the Facebook Platform
[rating] => 3.5
)
[3] => Array
(
[isbn] => 1847199488
[title] => CodeIgniter 1.7
[rating] => 3.5
)
[4] => Array
(
[isbn] => 059615593X
[title] => CSS Cookbook, 3rd Edition (Animal Guide)
[rating] => 3.5
)
)
所以它通过评级将它们排序，但不是按标题排列。我如何修改它，以便按评级排序，然后按标题排序？
为了它的价值，我也试过了：
if ($sort == 'rating-desc') {
foreach ($records as $key => $row) {
$rating[$key] = $row['rating'];
$title[$key] = $row['title'];
}
array_multisort($title, SORT_DESC, $rating, SORT_ASC, $records);
}
但结果也不正确。它显示了与我上面尝试过的相同的结果。
我错过了什么？
非常感谢，
马库斯
编辑：按照下面的一些建议，这里有几件我尝试过的事情。他们都没有解决我的问题。他们都返回正确排序的评级，但标题正在下降。
private function cmp($a, $b) {
if ($a['rating'] == $b['rating']) {
return strcasecmp($b['title'], $a['title']);
}
return $b['rating'] - $a['rating'];
}
private function cmp($a, $b) {
if ($a['rating'] == $b['rating'])
return strcasecmp($a['title'], $b['title']);
return $b['rating'] - $a['rating'];
}
if ($sort == 'rating-desc') {
foreach ($records as $key => $row) {
$rating[$key] = $row['rating'];
$title[$key] = $row['title'];
}
array_multisort($rating, SORT_DESC, $title, SORT_ASC, $records);
}
if ($sort == 'rating-desc') {
foreach ($records as $key => $row) {
$rating[$key] = $row['rating'];
$title[$key] = $row['title'];
}
array_multisort($rating, SORT_DESC, $title, SORT_DESC, $records);
}
这是我的整个代码示例 - 整个模型......
class Browse_model extends Model {
function Browse_model() {
parent::Model();
}
function get_form_tags() {
$sql = 'select t.id, t.tag, coalesce(btc.count, 0) as count from tags as t left outer join (select tag_id, count(*) as count from books_tags group by tag_id) as btc on t.id = btc.tag_id order by count desc, tag asc';
$query = $this->db->query($sql);
$tags = $query->result();
return $tags;
}
function get_book_info($tags, $andor, $read, $sort) {
/*
* SELECT b.isbn, b.title, b.publisher, b.date, b.thumb, b.filename, b.pages, t.tag
* FROM books AS b
* INNER JOIN books_tags AS bt ON b.isbn = bt.book_id
* INNER JOIN tags AS t ON bt.tag_id = t.id
* ORDER BY b.title, t.tag
*/
switch ($sort) {
case 'alpha-desc':
$order = 'b.title DESC, t.tag';
break;
case 'date-desc':
$order = 'b.date DESC, b.title, t.tag';
break;
case 'date-asc':
$order = 'b.date, b.title, t.tag';
break;
default:
$order = 'b.title, t.tag';
break;
}
$this->db->select('b.isbn, b.title, b.publisher, b.date, b.thumb, b.filename, b.pages, t.tag');
$this->db->from('books AS b');
$this->db->join('books_tags AS bt', 'b.isbn = bt.book_id', 'inner');
$this->db->join('tags AS t', 'bt.tag_id = t.id', 'inner');
$this->db->order_by($order);
$query = $this->db->get();
$result = $query->result();
$counter = '';
$records = $meta = $tags = array();
$count = count($result);
$i = 1;
foreach ($result as $book) {
// If this is not the last row
if ($i < $count) {
// If this is the first appearance of this book
if ($counter != $book->isbn) {
// If the meta array already exists
if ($meta) {
// Add the combined tag string to the meta array
$meta['tags'] = implode(', ', $tags);
// Add the meta array
$records[] = $meta;
// Empty the tags array
$tags = array();
}
// Reset the counter
$counter = $book->isbn;
// Grab the book from Amazon
$amazon = $this->amazon->get_amazon_item($book->isbn);
// Collect the book information
$meta = array(
'isbn' => $book->isbn,
'title' => strip_slashes($book->title),
'publisher' => strip_slashes($book->publisher),
'date' => date('F j, Y', strtotime($book->date)),
'thumb' => $book->thumb,
'file' => $book->filename,
'pages' => $book->pages,
'rating' => $amazon->Items->Item->CustomerReviews->AverageRating,
'raters' => $amazon->Items->Item->CustomerReviews->TotalReviews
);
// Add the tag to the tags array
$tags[] = $book->tag;
} else {
// All we need is the tag
$tags[] = $book->tag;
}
// If this is the last row
} else {
// If this is the first appearance of this book
if ($counter != $book->isbn) {
// Grab the book from Amazon
$amazon = $this->amazon->get_amazon_item($book->isbn);
// Collect the book information
$meta = array(
'isbn' => $book->isbn,
'title' => strip_slashes($book->title),
'publisher' => strip_slashes($book->publisher),
'date' => date('F j, Y', strtotime($book->date)),
'thumb' => $book->thumb,
'file' => $book->filename,
'pages' => $book->pages,
'rating' => $amazon->Items->Item->CustomerReviews->AverageRating,
'raters' => $amazon->Items->Item->CustomerReviews->TotalReviews
);
}
// All we need is the tag
$tags[] = $book->tag;
// Add the combined tag string to the meta array
$meta['tags'] = implode(', ', $tags);
// Add the meta array
$records[] = $meta;
}
$i++;
}
echo '<code><pre>';
print_r($records);
echo '</pre></code>';
if ($sort == 'rating-desc') usort($records, array('browse_model', 'cmp'));
echo '<code><pre>';
print_r($records);
echo '</pre></code>';
return $records;
}
private function cmp($a, $b) {
if ($a['rating'] == $b['rating'])
return strcasecmp($b['title'], $a['title']);
return $b['rating'] - $a['rating'];
}
}
答案 0 :(得分：5)
您的数组按评分和标题排序。问题是你要区分大小写，'a'来自'Z'。
比较标题时，请尝试使用strcasecmp代替strcmp。
此外，如果评级始终是一个数字，您可能应该用数字而不是字符串比较评级。使用$b['rating'] - $a['rating']代替strcmp。
编辑：
我使用了你原来的相同功能和相同的数据，并制作了一个测试脚本。使用类中的函数并标记为private，PHP警告说usort的回调无效，但继续运行（不接触数组）。但是，使用标记为public的函数，它可以按预期工作。这让我相信PHP不喜欢你的回调属于私有函数，或者类名错误。
如果您希望能够使用私有函数，则usort的调用显然需要在同一个类中的函数中。否则usort会抱怨回调无效并拒绝运行。
class Stuff
{
public function sort(&$arr)
{
usort($arr, array('Stuff', 'cmp'));
}
private function cmp($a, $b)
{
$ratingCmp = $b['rating'] - $a['rating'];
if ($ratingCmp == 0) {
return strcasecmp($a['title'], $b['title']);
} else {
return $ratingCmp;
}
}
}
Stuff::sort($records);
print_r($records);
对我来说，这会打印出按评级递减的书籍，然后按标题递增。如果这对你不起作用，那就有点时髦了。
答案 1 :(得分：2)
使用简单的布尔比较运算符来比较数字字段，例如评级，而不是strcmp：
private function cmp($a, $b) {
if ($b['rating'] == $a['rating'])
return strcmp($b['title'], $a['title']);
return $b['rating'] - $a['rating'];
}
看起来你的评分和头衔都在下降;将您的strcmp更改为return strcmp($a['title'], $b['title'])，以按评分（降序）和标题（升序）排序。
答案 2 :(得分：1)
您也可以使用array_multisort()
已删除的代码
创建一些额外的数组，但完成工作;如果您将代码放入函数或方法中（通过引用传递$ record），那么这些代码将在函数退出时被销毁。
编辑：我看到你已经提出了你已经尝试过的问题。它怎么不起作用？
编辑：这对我有用：
foreach ($records as $rec) {
$rating[] = $rec['rating'];
$title[] = strtolower($rec['title']);
}
array_multisort($title, SORT_DESC, $rating, SORT_ASC, $records);
print_r($records);
另一个编辑：
鉴于此数组：
$records = array(
0 =>
array (
'isbn' => '1847199488',
'title' => 'CodeIgniter 1.7',
'rating' => 3.5,
),
1 =>
array (
'isbn' => '1847199488',
'title' => 'CodeIgniter 1.7',
'rating' => 3,
),
2 =>
array (
'isbn' => '1847199488',
'title' => 'CodeIgniter 1.7',
'rating' => 3.2,
),
3 =>
array (
'isbn' => '1847199488',
'title' => 'CodeIgniter 1.7',
'rating' => 4.5,
),
4 =>
array (
'isbn' => '059615593X',
'title' => 'CSS Cookbook, 3rd Edition (Animal Guide)',
'rating' => 3.5,
),
5 =>
array (
'isbn' => '0321637984',
'title' => 'Essential Facebook Development: Build Successful Applications for the Facebook Platform',
'rating' => 3.5,
),
6 =>
array (
'isbn' => '0980576857',
'title' => 'jQuery: Novice to Ninja',
'rating' => 4.5,
),
7 =>
array (
'isbn' => '0596157134',
'title' => 'Learning PHP, MySQL, and JavaScript: A Step-By-Step Guide to Creating Dynamic Websites (Animal Guide)',
'rating' => 4.5,
),
);
此代码：
foreach ($records as $rec) {
$rating[] = $rec['rating'];
$title[] = strtolower($rec['title']);
}
array_multisort($rating, SORT_DESC, SORT_NUMERIC, $title, SORT_ASC, SORT_STRING, $records);
var_export($records);
会产生这个：
array (
0 =>
array (
'isbn' => '1847199488',
'title' => 'CodeIgniter 1.7',
'rating' => 4.5,
),
1 =>
array (
'isbn' => '0980576857',
'title' => 'jQuery: Novice to Ninja',
'rating' => 4.5,
),
2 =>
array (
'isbn' => '0596157134',
'title' => 'Learning PHP, MySQL, and JavaScript: A Step-By-Step Guide to Creating Dynamic Websites (Animal Guide)',
'rating' => 4.5,
),
3 =>
array (
'isbn' => '1847199488',
'title' => 'CodeIgniter 1.7',
'rating' => 3.5,
),
4 =>
array (
'isbn' => '059615593X',
'title' => 'CSS Cookbook, 3rd Edition (Animal Guide)',
'rating' => 3.5,
),
5 =>
array (
'isbn' => '0321637984',
'title' => 'Essential Facebook Development: Build Successful Applications for the Facebook Platform',
'rating' => 3.5,
),
6 =>
array (
'isbn' => '1847199488',
'title' => 'CodeIgniter 1.7',
'rating' => 3.2,
),
7 =>
array (
'isbn' => '1847199488',
'title' => 'CodeIgniter 1.7',
'rating' => 3,
),
)