php前端回波打印“Array”作为值

Question

php foreach echo prints "Array" as value问了这个问题，但这里不是这样的

     try {require_once'libs/config.php';
    $con = new PDO($dsn, $user, $pass, $opt);
  $query = "SELECT * FROM table ";
  //first pass just gets the column names
  print "<table> \n";
  $result = $con->query($query);
  //return only the first row (we only need field names)
  $row = $result->fetch(PDO::FETCH_ASSOC);
  print "<thead> <tr> \n";
  foreach ($row as $field => $value){
   print " <th>$field</th> \n";
  } // end foreach
  print " </tr> </thead> <tbobdy> \n";
  //second query gets the data 
  $data = $con->query($query);
  $data->setFetchMode(PDO::FETCH_ASSOC);
  foreach($data as $row){

回波$row；//打印阵列

     print " <tr> \n";
      foreach ($row as $name=>$value){
           print "<td>$value</td>\n";       }
     } // end field loop
   print " </tr>  \n";
  } // end record loop
 // print "</tbody> </table> \n";
  } catch(PDOException $e) {
   echo 'ERROR: ' . $e->getMessage();
  } // end try
$con = null;
 ?>

Answer 1

这意味着$row是一个数组，而不是变量。你需要做print_r($row);而不是echo $row;

Answer 2

您需要在$value循环中打印foreach，因为它包含数组元素的值。

您的最后输出如下所示：

<?php
try {
    require_once 'libs/config.php';
    $con   = new PDO($dsn, $user, $pass, $opt);
    $query = "SELECT * FROM table ";
    //first pass just gets the column names
    print "<table> \n";
    $result = $con->query($query);
    //return only the first row (we only need field names)
    $row    = $result->fetch(PDO::FETCH_ASSOC);
    print "<thead> <tr> \n";
    foreach ($row as $field => $value) {
        print " <th>$value</th> \n";
    } // end foreach
    print " </tr> </thead> <tbobdy> \n";
    //second query gets the data 
    $data = $con->query($query);
    $data->setFetchMode(PDO::FETCH_ASSOC);
    foreach ($data as $Somefield => $SomeValue) {
        echo $SomeValue; // prints your disered output
        print " <tr> \n";
        foreach ($row as $name => $value) {
            print "<td>$value</td>\n";
        }
    } // end field loop
    print " </tr>  \n";
} // end record loop
// print "</tbody> </table> \n";
catch (PDOException $e) {
    echo 'ERROR: ' . $e->getMessage();
} // end try
$con = null;
?>
?>

Answer 3

我想我得到它了，foreach as ..不能回显一个完整的数组(它的键或值，或者两者兼而有之)，如果它是一个数组，它会在这里打印一个‘数组’，因为$data包含一个数组，它只打印‘数组’，这对于每个多维数组都是正确的，因为您可以从php文档中看到下面的示例。

    /* foreach example 4: multi-dimensional arrays */
$a = array();
$a[0][0] = "a";
$a[0][1] = "b";
$a[1][0] = "y";
$a[1][1] = "z";

foreach ($a as $v1) {
    foreach ($v1 as $v2) {
        echo "$v2\n";
    }
}

数据库的结果是多维数组。