PHP Find and delete specific line set in large text file - php

Question

I am trying to remove certain line set based on ipaddress in large text file having approx. 60,000 lines. Each line set starting from MaxBytes[ipaddress] and ending with </TABLE> and a blank line present between each line set. There is variation in table lines in text file.
Sample line set :
MaxBytes[192.168.1.1]: 10000 <--start line
<TABLE>
<TR><TD>IP Address:</TD><TD>192.168.1.1</TD></TR>
<TR><TD>Max Speed:</TD> <TD>300</TD></TR>
</TABLE> <-- end line (Need to delete lines from start to end line)
I am trying to find start line using below codes (supported by Yerke) but unable to find out way to find next line number containing </table> tag. I need to find out start and end line number of line set containing specific ipaddress and delete it.
I am a beginner in coding, so I might need extended guidance.
codes :
<?php
$dir = "example.txt";
$searchstrt = "192.168.1.1";
///// find details
function find_line_number_by_string($dir, $searchstrt, $case_sensitive=false ) {
$line_number = [];
if ($file_handler = fopen($dir, "r")) {
$i = 0;
while ($line = fgets($file_handler)) {
$i++;
//case sensitive is false by default
if($case_sensitive == false) {
$searchstrt = strtolower($searchstrt);
$line = strtolower($line);
}
//find the string and store it in an array
if(strpos($line, $searchstrt) !== false){
$line_number[] = $i;
}
}
fclose($file_handler);
}else{
return "File not exists, Please check the file path or dir";
}
return $line_number;
}
$line_number = find_line_number_by_string($dir, $searchstrt);
var_dump($line_number);
?>
Sample example.txt
MaxBytes[192.168.1.1]: 10000
<TABLE>
<TR><TD>IP Address:</TD><TD>192.168.1.1</TD></TR>
<TR><TD>Max Speed:</TD> <TD>300</TD></TR>
</TABLE>
MaxBytes[192.168.1.2]: 30000
<TABLE>
<TR><TD>IP Address:</TD><TD>192.168.1.1</TD></TR>
<TR><TD>Max Speed:</TD> <TD>300</TD></TR>
<TR><TD>Name:</TD> <TD>ABC</TD></TR>
</TABLE>
MaxBytes[192.168.1.3]: 10000
<TABLE>
<TR><TD>IP Address:</TD><TD>192.168.1.1</TD></TR>
<TR><TD>Max Speed:</TD> <TD>200</TD></TR>
<TR><TD>Location:</TD> <TD>INDIA</TD></TR>
</TABLE>
I found some workaround to get line numbers of line set containing desired ip address. Does anyone suggest better way to do it.
<?php
error_reporting(E_ALL);
ini_set('display_errors', TRUE);
ini_set('display_startup_errors', TRUE);
$dir = "example.txt";
$searchstrt = "192.168.1.2";
$searchend = "</TABLE>";
///// find details
function find_line_number_by_string($dir, $searchstrt, $case_sensitive=false ) {
$line_number = [];
if ($file_handler = fopen($dir, "r")) {
$i = 0;
while ($line = fgets($file_handler)) {
$i++;
//case sensitive is false by default
if($case_sensitive == false) {
$searchstrt = strtolower($searchstrt);
$line = strtolower($line);
}
//find the string and store it in an array
if(strpos($line, $searchstrt) !== false){
$line_number[] = $i;
}
}
fclose($file_handler);
}else{
return "File not exists, Please check the file path or dir";
}
return $line_number;
}
$line_number = find_line_number_by_string($dir, $searchstrt);
//var_dump($line_number);
$start = $line_number[0];
////////////////////////
function find_line_number_by_string1($dir, $searchend, $case_sensitive=false, $start) {
$line_number1 = [];
if ($file_handler1 = fopen($dir, "r")) {
$i = $start;
// $i = 0;
while ($line1 = fgets($file_handler1)) {
$i++;
//case sensitive is false by default
if($case_sensitive == false) {
$searchend = strtolower($searchend);
$line1 = strtolower($line1);
}
//find the string and store it in an array
if(strpos($line1, $searchend) !== false){
$line_number1[] = $i;
}
}
fclose($file_handler1);
}else{
return "File not exists, Please check the file path or dir";
}
return $line_number1;
}
$line_number1 = find_line_number_by_string1($dir, $searchend, $case_sensitive=false, $start);
$first = $line_number[0];
$last = $line_number1[0];
//var_dump($line_number1);
for ($x = $first; $x <= $last; $x++) {
echo "Line number to be delete : $x <br>";
}
?>

Answer 1

I found solution of my question. I have just added few more line in my existing code. Now its working fine as required.
$lines = file($dir, FILE_IGNORE_NEW_LINES);
for ($x = $first; $x <= $last; $x++) {
echo "Line number to be delete : $x <br>";
$lines[$x] = '';
unset($lines[$x]);
}
//var_dump($lines);
file_put_contents($dir , implode("\n", $lines));