Get random email address from CSV file - php

Question

I am developing a PHP application where I need to fetch 5 random email addresses from a CSV file and send to user.
I already worked with CSV file many times but don't know how to fetch randomly in limit.
NOTE: CSV file have more than 200k emails.
Any one have a idea or suggestion then please send me.

Answer 1

If CSV is too big and won't be saved in a DB
You'll have to loop through all of the rows in the CSV once to count them.
You'll have to call a random-number generator function (rand, mt_rand, others...) and parametrize it to output numbers from 0 to $count, and call it 5 times (to get 5 numbers).
You'll have to loop through all of the rows in the CSV again and only copy the necessary information for the rows whose number matches the randomly generated values.
Nota bene: don't use file_get_contents with str_getcsv. Instead use fopen with fgetcsv. The first approach loads the entire file to memory which we don't want to do. The second approach only read the file line-by-line.
If the CSV is too big and will be saved in a DB
Loop through the CSV rows and insert each record into the DB.
Use a select query with LIMIT 5 and ORDER BY RAND().
If the CSV is small enough to fit into memory
Loop through the CSV rows and create an array holding all of them.
You'll have to call a random-number generator function (rand, mt_rand, others...) and parametrize it to output numbers from 0 to array count, and call it 5 times (to get 5 numbers).
Then retrieve the rows from the big array by their index number -- using the randomly generated numbers as indexes.

Answer 2

If csv file is not too big you can load whole file to array to get something like
e[0] = 'someone1#somewhere.com';
e[1] = 'someone2#somewhere.com';
e[2] = 'someone3#somewhere.com';
then you can pick random email by e[rand(0, sizeof(e))];
and do this 5 times (with check for double items)

Answer 3

Read all emails from CSV then select random 5 email from email array.
To select 5 random number use array_rand function.
$email = array('test#test.com','test2#test.com','test3#test.com','test4#test.com','test5#test.com');
$output = array_rand($email, 5);
print_r($email); // will return random 5 email.
for large number try to use something like
$max = count($email);
$email_rand = array();
for ($i =0; $i<5; $i++)
{
$a = mt_rand(0, $max);
$email_rand[] = $email[$a];
}
print_r($email_rand);

Answer 4

<?php
$handle = fopen('test.csv', 'r');
$csv = fgetcsv($handle);
function randomMail($key)
{
global $csv;
$randomMail = $csv[$key];
return $randomMail;
}
$randomKey = array_rand($csv, 5);
print_r(array_map('randomMail', $randomKey));
This is small utility to achieve the thing you expect and change the declaration of randomMail function as you desired.

Answer 5

for($i=0;$i<5;$i++)
{
$cmd = "awk NR==$(($"."{RANDOM} % `wc -l < ~/Downloads/email.csv` + 1)) ~/Downloads/email.csv >> listemail.txt";
$rs = exec($cmd);
}
after you read list mail from listmail.txt