格式化Heredoc中的数组值

问题描述

我想知道为什么我无法在Heredoc中执行类似{number_format($row['my_number'])}的操作.有什么办法可以解决这个问题，而不必求助于下面的$myNumber这样的变量?

I was wondering why I can't do something like {number_format($row['my_number'])} inside a Heredoc. Is there any way around this without having to resort to defining a variable like $myNumber below?

查看了 http://www.php .net/manual/zh-CN/language.types.string.php#language.types.string.syntax.nowdoc ，但一无所获.

CODE

foreach ($dbh -> query($sql) as $row):
    $myNumber = number_format($row['my_number']);

    $table .= <<<EOT
          <tr>
          <td>{$row['my_number']}</td> // WORKS
          <td>$myNumber</td> // WORKS
          <td>{number_format($row['my_number'])}</td> // DOES NOT WORK!
          </tr>
EOT;
endforeach;

推荐答案

您可以使用{$变量表达式在HEREDOC字符串中执行函数.但是，您需要预先为函数名称定义一个变量:

You can execute functions in a HEREDOC string by using {$ variable expressions. You however need to define a variable for the function name beforehand:

$number_format = "number_format";

$table .= <<<EOT
      <tr>
      <td>{$row['my_number']}</td> // WORKS
      <td>$myNumber</td> // WORKS
      <td>{$number_format($row['my_number'])}</td> // DOES NOT WORK!
      </tr>

因此，这种方式打破了HEREDOC简洁的目的.

So this kind of defeats the HEREDOCs purpose of terseness.

出于可读性考虑，为此目的定义一个通用的/无效的函数名称(例如$expr = "htmlentities";)可能会更加有用.然后，您可以在heredoc或双引号中使用几乎所有复杂的表达式和所有全局函数:

For readability it might be even more helpful to define a generic/void function name like $expr = "htmlentities"; for this purpose. Then you can utilize almost any complex expression and all global functions in heredoc or doublequotes:

    "   <td>  {$expr(number_format($num + 7) . ':')}  </td>  "

我认为{$expr(对于遇到这种构造的任何人来说都更加明显. (否则，这只是一个奇怪的解决方法.)

And I think {$expr( is just more obvious to anyone who comes across such a construct. (Otherwise it's just an odd workaround.)

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