PHP - 如果文件存在，则将数据写入新文件，并在 foreach 循环中调用生成文件的每一行

Question

我有一段PHP代码如下:

$write_URLs = fopen("links/WriteURLs.txt", "w");
foreach ($list_URLs as $htmlLink) {
    GetURLs ($htmlLink);
    foreach ($URLs as $URL) {
    fwrite($write_URLs, $URL ."\n");
    }
}
fclose($write_URLs);

上述代码每次执行时都会将 URL 写入 links/WriteURLs.txt 上，因此 WriteURLs.txt 文件无法保存结果之前的执行。

问题是我想检查 links/WriteURLs.txt 是否存在，然后开始将 URL 写入新文件，例如 links/01- WriteURLs.txt、links/02-WriteURLs.txt、... .之后，我想开始从生成的文件中读取 URL(即不是所有文件，仅是上一步中生成的文件)links/WriteURLs.txt、links/01- WriteURLs.txt、links/02-WriteURLs.txt 或 ...，并为每个 URL 回显 HELLO WORLD。下面您可以看到我尝试开发的代码的不完整版本。你能帮我解决这个问题吗？谢谢

$i = 1;
$write_URLs = fopen("links".DIRECTORY_SEPARATOR. $i. "-WriteURLs.txt", "w");
if(file_exists($write_URLs)) {
    fclose($write_URLs);
    $new_write_URLs = fopen("links".DIRECTORY_SEPARATOR. $i++. "-WriteURLs.txt", "w");
} else {
    foreach ($list_URLs as $htmlLink) {
        GetURLs ($htmlLink);
        foreach ($URLs as $URL) {
        fwrite($new_write_URLs, $URL ."\n");
        }
    }    
}
fclose($new_write_URLs);
$trimmed = file(???????????, FILE_IGNORE_NEW_LINES);
foreach ($trimmed as $URL) {
    echo "Hello World";
}

Answer 1

如果您想从刚刚完成写入的文本文件中读取数据，您可以简单地跟踪正在使用的文件的名称，然后在稍后的读取过程中使用它，如下所示:

$i = 0;
do {
  $filename = "links".DIRECTORY_SEPARATOR . $i++ . "-WriteURLs.txt";
} while (file_exists($filename));

$write_URLs = fopen($filename, "w");

foreach ($list_URLs as $htmlLink) {
      $URLs = GetURLs ($htmlLink);
      foreach ($URLs as $URL) {
      fwrite($write_URLs, $URL ."\n");
    }
}    

fclose($write_URLs);
$trimmed = explode("\n",file_get_contents( $filename ) );
foreach ($trimmed as $URL) {
    echo "Hello World";
}