Question

我有一个名为“ playersArray”的数组，如下所示：

Array (
    [0] => Array ( [name] => Joe [holders] => 0 )
    [1] => Array ( [name] => Bob [holders] => 100 )
    [2] => Array ( [name] => Jake [holders] => 100 )
    [3] => Array ( [name] => Mike [holders] => 100 )
    [4] => Array ( [name] => Tim [holders] => -0.0145 )
    [5] => Array ( [name] => Frank[holders] => 100 ) 
    [6] => Array ( [name] => Scott [holders] => 0.0583 ) 
    [7] => Array ( [name] => Doug[holders] => 0.1308 ) 
    [8] => Array ( [name] => Tommy [holders] => 0.2516 ) 
    [9] => Array ( [name] => Eric [holders] => 100 ) 
)

我有一个函数可以通过“ holders”值对该数组进行排序：

function compareHolders($a, $b) {

    $aPoints < $a['holders'];
    $bPoints < $b['holders'];

    return strcmp($aPoints, $bPoints);

}

我遍历另一个数组来创建此数组：

foreach ($players as $player) {
    $player['name'] = $athlete['name'];
    $player['holders'] = $total_result_yesterday;
    $playersArray[] = $player;
}

我正在尝试按“ holder”值对数组进行排序：

usort($playersArray, 'compareHolders');

print_r($playersArray);

最后，我试图在新排序的数组中获得5个最高和5个最低的“ holder”值：

$first_5_players = array_slice($playersArray, 0, 5, true);
$last_5_players = array_slice($playersArray, -5);

但是，排序无法正常进行。到期值未按期望的顺序显示。如何使排序正常工作？谢谢！

Answer 1

您的排序功能compareHolders不正确。 $aPoints和$bPoints未定义。由于holders键的值是数字，因此可以使用比较运算符。尝试执行以下操作：

function compareHolders($a, $b) {
    if ($a['holders'] == $b['holders']) {
        // return 0 if equal
        return 0;
    }
    return ($a['holders'] > $b['holders']) ? -1 : 1;
}

Answer 2

您实际上并没有比较// create instance of dialog AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(this); // get inflater and inflate layour for dialogue LayoutInflater inflater = this.getLayoutInflater(); View dialogView = inflater.inflate(R.layout.alert_label_editor, null); // now set layout to dialog dialogBuilder.setView(dialogView); // create instance like this OR directly mentioned in layout Button button= (Button) dialogView.findViewById(R.id.label_field); button.setText("test label"); AlertDialog alertDialog = dialogBuilder.create(); // show dialog alertDialog.show();中的两个值，因为您没有声明compareHolders()和$aPpoints。

这应该有效：

$bPoints

或者您也可以返回：

function compareHolders($a, $b) {

    $aPoints = $a['holders'];
    $bPoints = $b['holders'];

    return strcmp($aPoints, $bPoints);

}

然后，您可以摆脱return strcmp($a['holders'], $b['holders']); ，因为您没有比较字符串。

按键值对数组排序，然后获得数组中的5个最高和最低值

2 个答案: