How to delete a line from the file with php?

Question

I have a file named $dir and a string named $line, I know that this string is a complete line of that file but I don\'t know its line number and I

Answer 1

This is also good if you're looking for a substring (ID) in a line and want to replace the old line with the a new line.

Code:

$contents = file_get_contents($dir);
$new_contents = "";
if (strpos($contents, $id) !== false) { // if file contains ID
    $contents_array = explode(PHP_EOL, $contents);
    foreach ($contents_array as &$record) {    // for each line
        if (strpos($record, $id) !== false) { // if we have found the correct line
            continue; // we've found the line to delete - so don't add it to the new contents.
        } else {
            $new_contents .= $record . "\r"; // not the correct line, so we keep it
        }
    }
    file_put_contents($dir, $new_contents); // save the records to the file
    echo json_encode("Successfully updated record!");
}
else {
    echo json_encode("failed - user ID ". $id ." doesn't exist!");
}

Example:

input: "123,student"

Old file:

ID,occupation

123,student

124,brick layer

Running the code will change file to:

New file:

ID,occupation

124,brick layer

Answer 2

Another approach is to read the file line by line until you find a match, then truncate the file to that point, and then append the rest of the lines.

Answer 3

Like this:

file_put_contents($filename, str_replace($line . "\r\n", "", file_get_contents($filename)));

Answer 4

$contents = file_get_contents($dir);
$contents = str_replace($line, '', $contents);
file_put_contents($dir, $contents);

Answer 5

It can be solved without the use of awk:

function remove_line($file, $remove) {
    $lines = file($file, FILE_IGNORE_NEW_LINES);
    foreach($lines as $key => $line) {
        if($line === $remove) unset($lines[$key]);
    }
    $data = implode(PHP_EOL, $lines);
    file_put_contents($file, $data);
}

Answer 6

this will just look over every line and if it not what you want to delete, it gets pushed to an array that will get written back to the file. see this

 $DELETE = "the_line_you_want_to_delete";

 $data = file("./foo.txt");

 $out = array();

 foreach($data as $line) {
     if(trim($line) != $DELETE) {
         $out[] = $line;
     }
 }

 $fp = fopen("./foo.txt", "w+");
 flock($fp, LOCK_EX);
 foreach($out as $line) {
     fwrite($fp, $line);
 }
 flock($fp, LOCK_UN);
 fclose($fp);