如何在PHP中动态地执行array_push()

Question

假设我们要将某个数组添加到多维数组中。我可以选择要添加到主数组的数组数但是99个数组呢?下面是我的代码，我可以改变$howmany来添加我需要的数组数量(最多4个数组):

function DB_SINGLE_EXE($query, array  $array_par, $howmany = 0 ,$column1 = "null", $column2 = "null", $column3 = "null", $column4 = "null"){
global $host;
global $dbname;
global $username;
global $password;
global $db;
try {
    $stmt = $db->prepare($query);
    $stmt->execute($array_par);
}catch(PDOException $e)
    {
    echo "ERROR: " . $query . "<br>" . $e->getMessage();
    }
if ($howmany > 0){
$rowF = $stmt->fetchAll();
if($rowF){ 
$hell = count($rowF);
$stack = array(array("true" , $hell));
    foreach ($rowF as $row) {
        switch ($howmany) {
        case 1:
            array_push($stack, array($row[$column1]));
            break;
        case 2:
            array_push($stack, array($row[$column1], $row[$column2]));
            break;
        case 3:
            array_push($stack, array($row[$column1], $row[$column2], $row[$column3]));
            break;
        case 4:
            array_push($stack, array($row[$column1], $row[$column2], $row[$column3], $row[$column4]));
            break;
        }
    }
}else{
$stack = array(array("false" , "0"));
}  
return $stack;
}
}

如何调用函数:

$temp_query = "SELECT * FROM users WHERE status=:one";
$temp_array = array(":one" => "OK");
$results =DB_SINGLE_EXE($temp_query, $temp_array, 4, "user", "pw", "a_succ", "m_succ");
if ($results[0][0]="true"){
$username = $results[1][0];
$password = $results[1][1];
$suc = $results[1][2];
$m_suc = $results[1][3];
// Here I want to get more results but in function I just limited to 4 outputs. It might be 99 or even more and I don't want to use "select case" for 99 cases!
}

Answer 1

如果你使用PHP 5.6，你可以使用省略号(…)语法。如果不跳到最后。示例来自php.net:

<?php
function sum(...$numbers) {
    $acc = 0;
    foreach ($numbers as $n) {
        $acc += $n;
    }
    return $acc;
}
echo sum(1, 2, 3, 4);
?>

那么你的函数就会变成两个循环。

编辑:为了使事情更简单，下面是转换后的代码

function DB_SINGLE_EXE(...$columns){
    $stack = array(array("foo" , "bar"));
    foreach ($rowF as $row) {
        $arr=array();
        foreach($columns as $col) {
            $arr[]=$row[col];
        }
        array_push($stack, $arr);
    }
    return $stack;
}
DB_SINGLE_EXE("id", "name", "age");

不使用省略号也可以这样做，只需传递一个列数组:

function DB_SINGLE_EXE($columns){
    $stack = array(array("foo" , "bar"));
    foreach ($rowF as $row) {
        $arr=array();
        foreach($columns as $col) {
            $arr[]=$row[col];
        }
        array_push($stack, $arr);
    }
    return $stack;
}
DB_SINGLE_EXE(array("id", "name", "age"));

Answer 2

我很难解释您要做的事情，所以这可能工作，也可能不工作，因为所提供的代码实际上无法进行比较。看起来您需要从SELECT *结果集中取出某些列，或者类似的东西。假设是这样，最好只修改查询以获取所需的内容，然后使用基本的fetchAll()方法。

然而，假设由于某种原因您不能这样做，看看这是否适合您。我在这里初始化了一个$rowF变量，就像我期望的那样，当你的代码运行。如果这是不正确的，这可能是错误的，但这里是:

function DB_SINGLE_EXE(array $columnsToPush) {
    $rowF = array(array('col1' => 'col1val', 'col2' => 'col2val', 'cola' => 'colaval', 'colb' => 'colbval'));
    $stack = array(array('foo', 'bar'));
    foreach ($rowF as $row) {
        $toBePushed = array();
        foreach ($columnsToPush as $columnName) {
            $toBePushed[] = $row[$columnName];
        }
        $stack[] = $toBePushed;
    }
    return $stack;
}
DB_SINGLE_EXE(array('col1', 'cola'));

一些完整性检查，以确保行中存在的列名是有序的，当然还有其他加固。

编辑

看到完整的功能后，虽然我对设计有些担心，但我认为您可以使用:

大大简化事情。

function DB_SINGLE_EXE($query, array  $array_par){
    global $host;
    global $dbname;
    global $username;
    global $password;
    global $db;
    try {
        $stmt = $db->prepare($query);
        $stmt->execute($array_par);
    } catch (PDOException $e) {
        echo "ERROR: " . $query . "<br>" . $e->getMessage();
        // should probably return here, or do something to halt further execution
    }
    return $stmt->fetchAll();
}

…

$results = DB_SINGLE_EXE($temp_query, $temp_array);
if (!empty($results)) {
    // wrap in foreach if appropriate
    $username = $results[0]['user'];
    $password = $results[0]['pw'];
    $suc      = $results[0]['a_succ'];
    $m_suc    = $results[0]['m_succ'];
}

Answer 3

向函数传递99个参数似乎是一个开销。为什么不能将列作为数组传入。这将允许您传入任意数量的列键(甚至超过99);)

function DB_SINGLE_EXE( $rowF, $columns ){
  $columns = array_flip( $columns );
  $stack = array( array( "foo" , "bar" ) );
  foreach ($rowF as $row) {
    array_push( $stack, array_intersect_key( $row, $columns ) );
  }
  return $stack;
}
$result = DB_SINGLE_EXE(array(
    array(
      'col1' => 'aaa1',
      'col2' => 'bbb1'
    ),
    array(
      'col2' => 'bbb2',
      'col3' => 'ccc2'
    ),
    array(
      'col1' => 'aaa3',
      'col2' => 'bbb3',
      'col3' => 'ccc3'
    ),
    array(
      'col1' => 'aaa3',
      'col5' => 'eee3',
      'col6' => 'fff3'
    )
  ), array('col1', 'col2', 'col3'));