Operations on date PHP

Question

I need to make some operations on date. From the DB script is reading a date and frequency of actions (ex. 21 days), and should calculate when will be the next action since actual date. I've tried to do this in some ways (it's hard to me to write it in English, so below you can find the code).

    //$unix_on - date from DB
    //$devices[$i]['freq'] - frequency of actions
    $unix_on=strtotime($devices[$i]['date_on']);
    $unix_today=strtotime(date('Y-m-d'));
    $actions=($unix_today-$unix_on)/(86400*$devices[$i]['freq']);
    $b=explode(".", $actions);
    $a='0'.'.'.$b['1'];
    $f=$a*$devices[$i]['freq'];
    $d=$unix_today+($f*86400);
    $e=date("Y-m-d",$d);

But it not work's fine - there are errors in calculations, and I don't know why.

Please use the search function. [How to add time](http://stackoverflow.com/search?q=add+time+php) has been asked and answered countless times before — Gordon, Mar 10 '13 at 16:03

score 1 · Answer 1 · answered Mar 10 '13 at 15:53

1

strtotime is a lot more powerful than you're using it for. Try this:

$e = date("Y-m-d",strtotime($devices[$i]['date_on']." +".$devices[$i]['freq']."days"));

answered Mar 10 '13 at 15:53

Niet the Dark Absol

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this is exactly the kind of answers you got critizised for in your nomination – Gordon Mar 10 '13 at 16:05

score 1 · Answer 2 · answered Mar 10 '13 at 15:54

1

$dateOn = new DateTime($devices[$i]['date_on']);
$frecuency = new DateInterval('P' . $devices[$i]['freq'] . 'D'); // Period of x Days

$dateOn->add($frequency);

$e = $dateOn->format('Y-m-d');

See http://es2.php.net/manual/en/datetime.construct.php, http://es2.php.net/manual/en/datetime.add.php and http://es2.php.net/manual/en/dateinterval.construct.php

answered Mar 10 '13 at 15:54

Maks3w

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Thanks a lot for your help. Code works, but only for the first action - it doesn't showing next date since actual date... – kacper Mar 10 '13 at 22:44

Operations on date PHP

2 Answers2