对具有混合类型值的数组进行数值排序

$fruits = array(
    "lemon",
    "Lemon",
    20,
    "banana",
    "apple",
    "121",
    40,
    50
);

sort($fruits, SORT_NUMERIC);
foreach ($fruits as $key => $val) {
    echo "fruits[" . $key . "] = " . $val . "'n";
}

fruits[0] = apple
fruits[1] = lemon
fruits[2] = banana
fruits[3] = Lemon
fruits[4] = 20
fruits[5] = 40
fruits[6] = 50
fruits[7] = 121

OP，既然sort();不能很好地处理大写和小写字符，为什么不将所有内容转换为小写然后排序?

<?php
$fruits = array("lemon","Lemon", 20, "banana", "apple","121",40,50);
$fruits = array_map("strtolower", $fruits); //using strtolower
sort($fruits );
foreach ($fruits as $key => $val) {
    echo "fruits[" . $key . "] = " . $val . "'n";
}
?>

输出

fruits[0] = 20
fruits[1] = 40
fruits[2] = 50
fruits[3] = 121
fruits[4] = apple
fruits[5] = banana
fruits[6] = lemon
fruits[7] = lemon

基本上它应该排序从A到Z然后按数字顺序，但使用混合类型的函数不知道如何排序数组，并给出一个随机结果…

在手册页有一个巨大的警告说:

在对带有混合类型值的数组进行排序时要小心，因为sort()会产生不可预测的结果。

你可以给函数添加一个参数:

• SORT_REGULAR -正常比较项目(不改变类型)

• SORT_NUMERIC -比较数字项

• SORT_STRING -比较项目作为字符串

• SORT_LOCALE_STRING -根据当前语言环境将项目作为字符串进行比较。在PHP 4.4.0和5.0.2中添加，它使用系统语言环境，可以使用setlocale()更改。

根据手册在这里php.net

编辑1:也许你可以使用标志SORT_REGULAR获得最佳排序结果，因为它不会改变变量类型，数字仍然是数字，字符串仍然是字符串，但它也会给你一个奇怪的结果

fruits[0] = 121
fruits[1] = Lemon
fruits[2] = apple
fruits[3] = banana
fruits[4] = lemon
fruits[5] = 20
fruits[6] = 40
fruits[7] = 50

我认为是因为它比较了字符串的字母和L在a b l之前的ascii码…121排在第一位，因为你把它写成字符串"121"

编辑2:

最好的方法是分开类型:(这样php将把"121"作为一个数字而不是字符串，但你可以简单地通过if子句来决定)

<?php
$fruits = array("lemon","Lemon", 20, "banana", "apple","121",40,50);
$arr1=array();
$arr2=array();
      foreach($fruits as $key=>$val){
          if (is_numeric($val))
               array_push($arr1,$val); 
          else
              array_push($arr2,$val);
      }          
sort($arr1,SORT_NUMERIC);            
sort($arr2,SORT_LOCALE_STRING);
$fruits = array_merge($arr1,$arr2);
echo "<pre>";
foreach ($fruits as $key => $val) {
    echo "fruits[" . $key . "] = " . $val . "'n";
}
?>

我相信sort($array, SORT_NUMERIC)，不能转换为数字的值被视为0并以这种方式排序。由于示例中的所有字符串都变为0，因此柠檬是否出现在香蕉之前实际上根本无关紧要。下面是一个例子:

<?php
$fruits = array("alpha", "bravo", -1, -0.001, 0, 0.001, 1, "x-ray", "zulu");
shuffle($fruits); // randomly re-arrange the items in array
sort($fruits, SORT_NUMERIC);
print_r($fruits);
// output -- pass 1
Array
(
    [0] => -1
    [1] => -0.001
    [2] => 0
    [3] => alpha
    [4] => x-ray
    [5] => zulu
    [6] => bravo
    [7] => 0.001
    [8] => 1
)
// output -- pass 2
Array
(
    [0] => -1
    [1] => -0.001
    [2] => bravo
    [3] => zulu
    [4] => 0
    [5] => x-ray
    [6] => alpha
    [7] => 0.001
    [8] => 1
)
// output -- pass 3
Array
(
    [0] => -1
    [1] => -0.001
    [2] => x-ray
    [3] => zulu
    [4] => 0
    [5] => bravo
    [6] => alpha
    [7] => 0.001
    [8] => 1
)
?>