Problem in find Max And Min Number in Large Text File

PHP
1

hi
i have big file,in this link

im reading the numbers from each line,and each line have two number,

i wana find max and min value, i wrote a code that worked on little text file but in this file dont work, its seems be ok,but i dont know what i missed
its my code


<?php 
$time_start = microtime(true);
echo "Labour:";
ini_set('max_execution_time', 360);
echo "<br>" ;
ini_set('memory_limit', '2048M');
$sumpage = array();;
  $file = fopen( "web-graph.txt", "r" ) or exit ( "Unable to open file!" ) ;
  $str = fgets($file);
 $tmp = explode(" ", $str);
 if ($tmp[0]>$tmp[1]) {
      $max=$tmp[0];
      $min=$tmp[1];
  } else {
      $max=$tmp[1];
      $min=$tmp[0];
  }

  while ( !feof ( $file ) )
    {    
     $tmp = explode(" ", $str);
     if ($tmp[0]>$max) {
         $max=$tmp[0];
     }if ($tmp[0]<$min){
         $min=$tmp[0];
     } 
     if ($tmp[1]>$max) {
         $max=$tmp[1];
     }if ($tmp[1]<$min){
         $min=$tmp[1];
     }
     $str = fgets($file);
  }
     echo "Max =".$max."Min:".$min; // number of lines in file
  echo "<br>";
  fclose( $file ) ;
   echo "<br>";
    $time_end = microtime(true);
    $time = $time_end - $time_start;
    echo "Time of Execute: {$time}";
 ?>
2

Could you be more specific?
Do you get an error, a blank page, a wrong result? What does “dont work” mean?

1 Like
3

If I understood correctly then this may work.

$file = fopen('web-graph.txt', 'r' ) or exit ('Unable to open file!');
list($min, $max) = fscanf($file, '%s %s');
while (!feof($file)) {
  list($a, $b) = fscanf($file, '%s %s');
  $max = max($a, $b, $max);
  $min = min($a, $b, $min);
}
fclose($file);
echo "Min $min\nMax $max";
1 Like
4

hi sory for late,
no…its show the biggest number is 99999 but the real biggest number is something bigger

5

thanks
yes…its worked for muximum ,but minimum is null…Can you explain it?

6

If any line in the file contains only one number, and you don’t check for that, then it will present as a null string which will evaluate as lower than ‘1’.

1 Like
7

I’ve updated my example if you wish to try it.

$file = fopen('web-graph.txt', 'r') or exit('Unable to open file!');
list($a, $b) = fscanf($file, '%s %s');
$min = PHP_INT_MAX;
$max = ~PHP_INT_MAX;
while (!feof($file)) {
    $max = max($a, $b, $max);
    $min = min($a, $b, $min);
    list($a, $b) = fscanf($file, '%s %s');
}
fclose($file);
echo "Min $min\nMax $max";
1 Like
8

thanks in advance,its worked,

9

yes,thats right,

now code works fine,

10

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