Delete rows from a file based on an array I got from a sql query

Question

Hi guys I have a text file that contains several lines, let's say:

line1
line2
line3
line4
line5

based on a query to a mysql database I get some values, for example

line1
line3

I want to take the array from the query and delete those values from the text file so that the result is:

line2
line4
line5

I don't have problems to get the values from the db, my problem is how to delete the lines from the text file?

Answer 1

Something like this if there is only one instance of the value in the file:

$rows = your_fetch_all_func();  //or while($rows[] = your_fetch_assoc_func()) {}
$lines = file('path/to/file.txt', FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);

foreach($rows as $row) {
    if($key = array_search($row['column'], $lines)) {
        unset($lines[$key]);
    }
}

If the data from the database can be in the file more than once, then use something like this, though there is probably a slicker way:

foreach($rows as $row) {
    if($keys = array_keys($lines, $row['column'])) {
        foreach($keys as $key) {        
            unset($lines[$key]);
        }
    }
}