I am fetching data from a text file where I need to match the substring to get the matched line. Once, I have that, I need to get the third 8 digit value in the line which comes after the delimiter "|". Basically, all the values have varying lengths and are separated by a delimiter "|". Except the first substring (id) which is of fixed length and has a fix starting and end position.

Text file data example:

    0123456|BHKAHHHHkk|12345678|JuiKKK121255
    9100450|HHkk|12348888|JuiKKK10000000021sdadad255

$file = 'file.txt';


// the following line prevents the browser from parsing this as HTML.
header('Content-Type: text/plain');

// get the file contents, assuming the file to be readable (and exist)
$contents = file_get_contents($file);
// escape special characters in the query
$txt = explode("\n",$contents);

$counter = 0;
foreach($txt as $key => $line){
    $subbedString = substr($line,2,6);

   // $searchfor = '123456';
    //echo strpos($subbedString,$searchfor); 
    if(strpos($subbedString,$searchfor) === 0){
        $matches[$key] = $searchfor;
        $matchesLine[$key] = substr($line,2,50);
          echo  "<p>" . $matchesLine[$key] . "</p>";
          
                  $counter  = 1;
                  if($counter==10) break;
         
    }

    

CodePudding user response：

1. If you need to divide file's contents by line breaks, it's always better to use file function
2. To divide line into parts with unknown length by a delimiter, use explode function.

Code:

$file = 'file.txt';
$txt = file($file);

$counter = 0;
foreach ($txt as $key => $line) {
    $line = \trim($line);
    $substrings = explode('|', $line);
    
    if (\count($substrings) === 0) {
        continue;
    }

    $searchFor = '123456';
    if (substr($substrings[0], 1) === $searchFor) {
        if (!isset($substrings[2]) {
            continue;
        }

        $matches[$key] = $searchFor;

        $matchesLine[$key] = $line;
        echo  "<p>" . $substrings[2] . "</p>";

        if (  $counter === 10) {
            break;
        }
    }
}

I also noticed that in your example there are 7-digit ids, while you were talking about 6 digits (and the $searchfor variable didn't match anything)

CodePudding user response：

Use

^(\d )\|[^|]*\|(\d{8})\|

See regex proof.

EXPLANATION

--------------------------------------------------------------------------------
  ^                        the beginning of the string
--------------------------------------------------------------------------------
  (                        group and capture to \1:
--------------------------------------------------------------------------------
    \d                       digits (0-9) (1 or more times (matching
                             the most amount possible))
--------------------------------------------------------------------------------
  )                        end of \1
--------------------------------------------------------------------------------
  \|                       '|'
--------------------------------------------------------------------------------
  [^|]*                    any character except: '|' (0 or more times
                           (matching the most amount possible))
--------------------------------------------------------------------------------
  \|                       '|'
--------------------------------------------------------------------------------
  (                        group and capture to \2:
--------------------------------------------------------------------------------
    \d{8}                    digits (0-9) (8 times)
--------------------------------------------------------------------------------
  )                        end of \2
--------------------------------------------------------------------------------
  \|                       '|'

Sample code:

<?php

$re = '/^(\d )\|[^|]*\|(\d{8})\|/m';
$str = '0123456|BHKAHHHHkk|12345678|JuiKKK121255
9100450|HHkk|12348888|JuiKKK10000000021sdadad255';

preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);

// Print the entire match result
var_dump($matches);

Sample output:

array(2) {
  [0]=>
  array(3) {
    [0]=>
    string(28) "0123456|BHKAHHHHkk|12345678|"
    [1]=>
    string(7) "0123456"
    [2]=>
    string(8) "12345678"
  }
  [1]=>
  array(3) {
    [0]=>
    string(22) "9100450|HHkk|12348888|"
    [1]=>
    string(7) "9100450"
    [2]=>
    string(8) "12348888"
  }
}