How to remove duplicate emails in csv file - php

Question

How to remove duplicate email address in different csv file
example:
I have 10.000 emails address (all_members.csv) after sent out > Then I received 2550 invalid email (invalid.csv)
I want to remove that "invalid email"
My Code "
<?php
$all = file('all_email.csv'); // all_members.csv
$invalid = file('invalid.csv'); // invalid_email.csv
$correctEmails=array_diff($all, $invalid);
foreach ($correctEmails as $email) { echo $email."<br>"; }
$result = array_intersect($all,$invalid);
?>
for remove email only > this php code is work.
the problem is if I want to remove emails under "Multiple columns" is Not work
anyone can help
I would greatly appreciate if you able to help me, thanks

Answer 1

I'd recommend encapsulating this in a function that streams each line, builds an array of field -> values then checks to see if the value is in the data you want to remove, if it's not, write the line to an out file.
Something like...
<?php
/**
* Given a CSV file to read, the delimiter, and what to remove, return the filtered CSV data
* #param $filename string The /path/to/file.csv
* #param $outputFile string Where to write the output CSV data to
* #param $delimiter string How the fields are delimited in the CSV
* #param $removeHeader string The header to remove data from
* #param $removeData array The data to omit from the output
*
* #return boolean
**/
function remove_duplicates($filename, $outputFile, $delimiter=',', $removeHeader, $removeData)
{
// If the file doesn't exist or isn't readable - return false
if(!file_exists($filename) || !is_readable($filename)) {
return false;
}
$header = null;
$validData = [];
$writeHandle = fopen($outputFile, 'w');
if (false !== ($readHandle = fopen($filename, 'r'))) {
//While there are rows in the CSV, get this as an array of values
while (false !== ($row = fgetcsv($readHandle, 1000, $delimiter))) {
//On the first iteration, get the headers from the CSV
if (!$header) {
$header = $row;
fputcsv($writeHandle, $header);
} else {
// Combine the headers with the row to create an associative array representing a line
$line = array_combine($header, $row);
// Looking at the removeHeader field in this line, check to see if the value is in removeData
if (!in_array($line[$removeHeader], $removeData) {
// If it's not, then it's a valid line
fputcsv($writeHandle, $line);
}
}
}
fclose($readHandle);
fclose($writeHandle);
}
// Return
return true;
}