给定这个数组:
$inventory = array(
array("type"=>"fruit", "price"=>3.50),
array("type"=>"milk", "price"=>2.90),
array("type"=>"pork", "price"=>5.43),
);
我想按价格排序$inventory的元素,以获得:
$inventory = array(
array("type"=>"pork", "price"=>5.43),
array("type"=>"fruit", "price"=>3.50),
array("type"=>"milk", "price"=>2.90),
);
我该怎么做呢?
$arr1 = array(
array('id'=>1,'name'=>'aA','cat'=>'cc'),
array('id'=>2,'name'=>'aa','cat'=>'dd'),
array('id'=>3,'name'=>'bb','cat'=>'cc'),
array('id'=>4,'name'=>'bb','cat'=>'dd')
);
$result1 = array_msort($arr1, array('name'=>SORT_DESC);
$result2 = array_msort($arr1, array('cat'=>SORT_ASC);
$result3 = array_msort($arr1, array('name'=>SORT_DESC, 'cat'=>SORT_ASC));
function array_msort($array, $cols)
{
$colarr = array();
foreach ($cols as $col => $order) {
$colarr[$col] = array();
foreach ($array as $k => $row) { $colarr[$col]['_'.$k] = strtolower($row[$col]); }
}
$eval = 'array_multisort(';
foreach ($cols as $col => $order) {
$eval .= '$colarr[\''.$col.'\'],'.$order.',';
}
$eval = substr($eval,0,-1).');';
eval($eval);
$ret = array();
foreach ($colarr as $col => $arr) {
foreach ($arr as $k => $v) {
$k = substr($k,1);
if (!isset($ret[$k])) $ret[$k] = $array[$k];
$ret[$k][$col] = $array[$k][$col];
}
}
return $ret;
}
这个函数是可重用的:
function usortarr(&$array, $key, $callback = 'strnatcasecmp') {
uasort($array, function($a, $b) use($key, $callback) {
return call_user_func($callback, $a[$key], $b[$key]);
});
}
默认情况下,它在字符串值上工作得很好,但如果所有值都是数字,则必须为数字比较函数指定子回调函数。
完整的动态功能
我跳到这里进行关联数组排序,并在http://php.net/manual/en/function.sort.php上找到了这个惊人的函数。这个函数是非常动态的,用指定的键按升序和降序排序。
按特定键对数组排序的简单函数。维护索引关联
<?php
function array_sort($array, $on, $order=SORT_ASC)
{
$new_array = array();
$sortable_array = array();
if (count($array) > 0) {
foreach ($array as $k => $v) {
if (is_array($v)) {
foreach ($v as $k2 => $v2) {
if ($k2 == $on) {
$sortable_array[$k] = $v2;
}
}
} else {
$sortable_array[$k] = $v;
}
}
switch ($order) {
case SORT_ASC:
asort($sortable_array);
break;
case SORT_DESC:
arsort($sortable_array);
break;
}
foreach ($sortable_array as $k => $v) {
$new_array[$k] = $array[$k];
}
}
return $new_array;
}
$people = array(
12345 => array(
'id' => 12345,
'first_name' => 'Joe',
'surname' => 'Bloggs',
'age' => 23,
'sex' => 'm'
),
12346 => array(
'id' => 12346,
'first_name' => 'Adam',
'surname' => 'Smith',
'age' => 18,
'sex' => 'm'
),
12347 => array(
'id' => 12347,
'first_name' => 'Amy',
'surname' => 'Jones',
'age' => 21,
'sex' => 'f'
)
);
print_r(array_sort($people, 'age', SORT_DESC)); // Sort by oldest first
print_r(array_sort($people, 'surname', SORT_ASC)); // Sort by surname
在php中,根据给定key的值对关联数组进行排序:
通过使用usort (http://php.net/usort),我们可以按升序和降序对数组进行排序。只是我们需要创建一个函数,并将其作为参数传递给usort。按照下面的例子,使用大于表示升序,如果我们通过小于条件,那么它将按降序排序。
例子:
$array = array(
array('price'=>'1000.50','product'=>'test1'),
array('price'=>'8800.50','product'=>'test2'),
array('price'=>'200.0','product'=>'test3')
);
function cmp($a, $b) {
return $a['price'] > $b['price'];
}
usort($array, "cmp");
print_r($array);
输出:
Array
(
[0] => Array
(
[price] => 200.0
[product] => test3
)
[1] => Array
(
[price] => 1000.50
[product] => test1
)
[2] => Array
(
[price] => 8800.50
[product] => test2
)
)
我的结尾是这样的:
function sort_array_of_array(&$array, $subfield)
{
$sortarray = array();
foreach ($array as $key => $row)
{
$sortarray[$key] = $row[$subfield];
}
array_multisort($sortarray, SORT_ASC, $array);
}
只需调用函数,传递数组和第二级数组字段的名称。
如:
sort_array_of_array($inventory, 'price');