Question

I am in need to open a text file (file.txt) which contains data in the following format

ai
bt
bt
gh
ai
gh
lo
ki
ki
lo

ultimately I want to remove all the duplicate lines so only one of each data remains. So the result would look like this

ai
bt
gh
lo
ki

any help with this would be awesome

Answer 1

This should do the trick:

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

file() reads the file and puts every line in an array.

array_unique() removes duplicate elements from the array.

Also, to put everything back into the file:

file_put_contents('file.txt', implode($lines));