Grab and Explode Data | 易学教程

问题

I'm sort of new to PHP, and I need some help on exploding data from a file. The file in question is: http://data.vattastic.com/vatsim-data.txt

Basically, I need to get the data under the !CLIENTS: section (near the bottom). With this data, I need to explode it and get the info between each :.

I have tried with this code, but it gives me a variable offset error (Undefined offset: 3)

$file = file("http://data.vattastic.com/vatsim-data.txt");
foreach($file as $line)
{
   $data_record = explode(":", $line);

   // grab only the data that has "ATC" in it...
   if($data_record[3] == 'ATC' && $data_record[16] != '1' && $data_record[18] != '0'&&   stristr($data_record[0],'OBS') === FALSE)
   {
        rest of code here...
   }
}

If someone could help me with this, I'd greatly appreciate it.

回答1:

This happens because you are trying to explode rows like this:

; !GENERAL contains general settings

When you explode that line, you your $data_records looks like this:

Array ( [0] => ; !GENERAL contains general settings )

Quick solution:

$file = file("http://data.vattastic.com/vatsim-data.txt");
foreach($file as $line)
{
   if(strpos($line,';') === 0) continue ; // this is comment. ignoring
   $data_record = explode(":", $line);
   $col_count = count($data_record);

   switch($col_count) {
     case 42: // columns qty = 42, so this is row from `clients`
      // grab only the data that has "ATC" in it...
      if($data_record[3] == 'ATC' && $data_record[16] != '1' && $data_record[18] != '0'&&   stristr($data_record[0],'OBS') === FALSE)
      {
           rest of code here...
      }
      break;
     default:
       // this is other kind of data, ignoring
       break;
   }
}

回答2:

Another solution is to use regular expressions and look for !CLIENTS: section. This would also work in the case that the CLIENTS have more or less than 42 columns in the future

$file = file_get_contents ("http://data.vattastic.com/vatsim-data.txt");  
$matches = null;
preg_match ('/!CLIENTS:\s\n(.*)\n;/s' , $file, $matches );
if($matches)
{
  $client_lines = explode("\n", $matches[1]);
  foreach ($client_lines as $client)
  {
    $data_record = explode(":", $client);
    if($data_record[3] == 'ATC' && $data_record[16] != '1' && $data_record[18] != '0'&&   stristr($data_record[0],'OBS') === FALSE)
    {
      //rest of code here...
    }
  }
}

来源：https://stackoverflow.com/questions/12168543/grab-and-explode-data

标签

php

arrays

foreach

explode