Add 3 month to the given date in a loop PHP - php

Question

Hi i have the following date = 2015-06-01 00:00:00
so i have to add 3 month to this date , so write the following code
$sarting="2015-06-01 00:00:00";
$date[$i]=date('Y-m-d', strtotime($sarting . "+3 months") );
And i get the output = 2015-09-01;
But now i want to add 3 month again and again for 20 times and i have to store the output to array
so i write the following code
$store_date=array();
for($i=0;$i<20;$i++){
$store_date[$i]=date('Y-m-d', strtotime($sarting . "+3 months") );
}
But the thing it's returning 2015-09-01 20 times . i need like this 2015-09-01, 2015-12-01,2016-06-01 etc .
Please check

Answer 1

I would recommend using the DateTime-class so we can reuse the same instance on each iteration.
$sarting = "2015-06-01 00:00:00";
$store_date = [];
// Create a DateTime-object we can reuse
$date = new DateTime($sarting);
for ($i = 0; $i < 20; $i++) {
$date->modify('+3 months');
$store_date[] = $date->format('Y-m-d');
}
print_r($store_date);
Since we're resuing the same object, it will keep adding 3 months to it on each iteration. No need for any calculations or anything, making the code clean and readable.
Demo: https://3v4l.org/KZiH9

Answer 2

You can use PHP's dateTime class' modify() method to add +3 months in loop to it.
<?php
$dateStamp = "2015-06-01 00:00:00";
$date = new DateTime($dateStamp);
$datesArr = [];
for ($i=1; $i<21 ; $i++) {
$date->modify('+3 month');
$datesArr[] = $date->format('Y-m-d h:i:s');
}
echo '<pre>';
print_r($datesArr);
echo '</pre>';
Output:
Array
(
[0] => 2015-09-01 12:00:00
[1] => 2015-12-01 12:00:00
[2] => 2016-03-01 12:00:00
[3] => 2016-06-01 12:00:00
[4] => 2016-09-01 12:00:00
[5] => 2016-12-01 12:00:00
[6] => 2017-03-01 12:00:00
[7] => 2017-06-01 12:00:00
[8] => 2017-09-01 12:00:00
[9] => 2017-12-01 12:00:00
[10] => 2018-03-01 12:00:00
[11] => 2018-06-01 12:00:00
[12] => 2018-09-01 12:00:00
[13] => 2018-12-01 12:00:00
[14] => 2019-03-01 12:00:00
[15] => 2019-06-01 12:00:00
[16] => 2019-09-01 12:00:00
[17] => 2019-12-01 12:00:00
[18] => 2020-03-01 12:00:00
[19] => 2020-06-01 12:00:00
)
Working Code:

Answer 3

You are not changing the value of $sarting. Try this:
$sarting = "2015-06-01 00:00:00";
$store_date = array();
for ($i = 0; $i < 20; $i++) {
$sarting = $store_date[$i] = date('Y-m-d', strtotime($sarting . "+3 months"));
}

Answer 4

Try this check if it helps,
$sarting="2015-06-01 00:00:00";
$store_date=array();
for($i=0;$i<20;$i++){
$store_date[$i]=date('Y-m-d', strtotime($sarting . "+3 months") );
$sarting=$store_date[$i];
}
echo "<pre>";
print_r($store_date);
echo "</pre>";

Answer 5

Below code for Addition or Subtraction for Year/Month/day from date
Addition = date('Y-m-d', strtotime("+0 years +3 months +0 days", strtotime($lastdate)));
Subtraction = date('Y-m-d', strtotime("+0 years -3 months +0 days", strtotime($lastdate)));
$lastdate = "01-12-2015"; //actual date
$after_3_month = date('Y-m-d', strtotime("+0 years +3 months +0 days", strtotime($lastdate))); // adding 3 month on the actual date
echo $after_3_month; //3 month added with actual date