$row['column'] 在 PHP 中 [英] $row['column'] in PHP

问题描述

大家好，我看到了一个带有 $row['columnname'] 的代码.代码是

Hello guys I have seen a code with $row['columnname'].The code is

$myQuery = "SELECT * FROM information_schema.columns WHERE table_name = '$tabname'";
$re = mysql_query($myQuery);


while($row = mysql_fetch_array ($re)){
     if(!empty ($row)){
                $col_name = $row['COLUMN_NAME'];

      $myQuery = "SELECT ".$col_name." FROM ".$tabname." WHERE sampleid='".$sid."'";
                echo "<br>".$myQuery;
                $reqq = mysql_query($myQuery);
                $roww = mysql_fetch_array($reqq);
                echo "<br>".$roww[$col_name];

                }
            }

我的问题是$row[]在php中有什么用?

My question is what is the use of $row[] in php?

是用来嵌入列值如 $row['columnname'] 还是只是添加一个变量如 $row[$anyvariable].

Is it used to embed the column value like $row['columnname'] or just adding a variable like $row[$anyvariable].

推荐答案

这就是所谓的括号表示法.$row 是一个数组，它有属性.在这种情况下，它具有命名属性，因此它是一个关联数组.关联数组具有键/值对.它看起来像这样:

That is called bracket notation. $row is an array, which has properties. In this case, it has named properties, so it is an associative array. An associate array has key/value pairs. It looks like this:

$myArray = [
  'key' => 'value'
];

要回显上述属性的值，您可以使用 echo $myArray['key'];

To echo the value of the property above, you would use echo $myArray['key'];

在您包含的特定代码中，属性名称是COLUMN_NAME"并且它有一个值.代码将该值分配给变量 $col_name.

In the specific code you included, the property name is "COLUMN_NAME" and it has a value. The code assigns that value to the variable $col_name.

这是另一个示例用法，可帮助澄清所有这些:

Here's another sample usage to help clarify all of this:

$people = [
  'Susan' => [
    'Age' => 24,
    'Phone' => '555-123-4567'
  ],
  'Jack' => [
    'Age' => 27,
    'Phone' => '555-9876-5432'
  ]
];

echo $people['Jack']['Age']; // 27

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