PHP中while循环的替代方法

Question

I am trying to develop my understanding of php and would really appreciate any help. I have used a while loop to compare some values posted in my form with what is stored in a csv file. This code works well. However, is it possible to achieve the same result using a FOR EACH loop or even a Do Until?? Or both?? Many thanks for any support

$file_handle = fopen("games.csv", "r"); # identify which file is being used.
while(!feof($file_handle))
{
$gameinfo = fgetcsv($file_handle);
if ($gameinfo[0] == $_POST["gameID"])
{
$GameName = "$gameinfo[2]";
$GameCost = "$gameinfo[4]";
$GameFound = true;
}
}
fclose($file_handle);

Answer 1

while is the best suited statement for this task, because you want to check for EOF before doing any read.

You can transform it in a do-while (there is no do-until in PHP) as an exercise:

do
{
   if (!feof($file_handle))
   {
      $gameinfo = fgetcsv($file_handle);

      if ($gameinfo[0] == $_POST["gameID"])
      {
         ...
      }
   }
}
while(!feof($file_handle));

or shorter

do
{
   if (feof($file_handle))
      break;

   $gameinfo = fgetcsv($file_handle);

   if ($gameinfo[0] == $_POST["gameID"])
   {
      ...
   }
}
while(true);

but that's just a bad way to write a while .

Regarding foreach , quoting the doc

The foreach construct provides an easy way to iterate over arrays. foreach works only on arrays and objects, and will issue an error when you try to use it on a variable with a different data type or an uninitialized variable.

You can customize iteration over objects , this let you ( Warning , layman language) use foreach on "custom objects" so that you can, in a way, extend the functionality of foreach .
For example to iterate over CSV files you can use this class

<?php
class FileIterator implements Iterator
{
    private $file_handle = null;
    private $file_name;
    private $line;

    public function __construct($file_name)
    {
        $this->file_name = $file_name;

        $this->rewind();
    }

    public function rewind()
    {
        if (!is_null($this->file_handle))
            fclose($this->file_handle);

        $this->line = 1;
        $this->file_handle = fopen($this->file_name, "r");
    }

    public function current()
    {
        return fgetcsv($this->file_handle);
    }

    public function key() 
    {
        return $this->line;
    }

    public function next() 
    {
        return $this->line++;
    }

    public function valid()
    {
        $valid = !feof($this->file_handle);

        if (!$valid)
           fclose($this->file_handle);

        return $valid;
    }

}
?>

and use it this way

$it = new FileIterator("game.csv");

foreach ($it as $line => $gameObj) 
{
    echo "$line: " . print_r($gameObj, true) . "<br/>";
}

Which produce something like

1: Array ( [0] => 0 [1] => Far Cry 3 ) 
2: Array ( [0] => 1 [1] => Far Cry Primal ) 
3: Array ( [0] => 2 [1] => Alien Isolation )

for this file

0,Far Cry 3
1,Far Cry Primal
2,Alien Isolation