PHP: Calculate Age from DOB

[ner0]

Hey guys, since I\'ve spent a fair few hours working on this little snippet, I thought it\'d be worth sharing.. as I had to search around for some ideas before I settled on my code:

All dates are in YYYY-MM-DD format, $u[\'DOB\'] and &u[\'tzOffset\'] are values taken from a database containing user data, tzOffset is stored as the offset in hours (i.e. -5 / +2 / -3.5)

The final $m[\'age\'] is the value of the age, also included a check to see whether it\'s a person\'s actual birthday, incase you\'d like to do anything with that.

Ignore the insane comments... they were for me.

[code] //-- Calculate Age from DOB, times in YYYY-MM-DD FORMAT! --//
$dob = $u[\'DOB\'];

# get user timezone... i.e. what we can take away from server time (GMT/UTC)
$tz = $u[\'tzOffset\'];

# Get date of NOW, unfortunately, server TZ isn\'t GMT, to make it easier later, convert date INTO GMT here!
$t = time();

# How far in front/behind (of) GMT are we? (i.e. -0500)
$gmtDiff = date("O");

# make this figure usable (we need seconds)
$gmtDiff = ($gmtDiff / 100) * 3600; # here we just turn the -0500 into -5 (-5 hours) then multiply by 3600 (secs per hour =D)

# TRUE GMT TIME NOW?
$t = $t - $gmtDiff;

# User\'s Timezone offset? (in seconds)
$tz = $tz * 60 * 60;

# User\'s LOCAL TIME?.. hmm, this could be useful globally?.. yup yup.
$uTime = $t + $tz;
$m[\'uTime\'] = $uTime; // worth noting this is global\'ed as a unix timestamp

# Grab both dates as $n and $b (now and birthdate) arrays
$n = explode("-",date("Y-m-d",$uTime));
$b = explode("-",$dob);

# Age step 1, check years..
$age = $n[0] - $b[0];

# Are we BEFORE their birth month?
if ($n[1] < $b[1])
{
$age--;
}

# Are we IN their birth month?
else if ($n[1] == $b[1])
{
# current month / birth month.. are we before, or on their birthday?
if ($n[2] < $b[2])
{
$age--;
}
else if ($n[2] == $b[2])
{
$m[\'bday\'] = "y";
}
}
# Otherwise, we\'ve passed.. or are on their birthday. so the original calc of this year minus birth year is correctimondo =]!

$m[\'age\'] = $age;[/code]

There will be much more elegant ways of doing this, I tried using timestamp difference to begin, though it was late and I couldn\'t think of the impact leap years would make.

Hope this is useful for someone!

[Josh]

ROFL! You use comments like I do hahaha. They do work too /biggrin.gif\' class=\'bbc_emoticon\' alt=\':D\' />

[ner0]

I like to use comments to \'vent\'... especially when I\'ve been stuck coding strictly to php for so long, it\'s nice to go insane for a while lol

and for some reason using the \'explode()\' command always makes me chuckle /blink.gif\' class=\'bbc_emoticon\' alt=\':blink:\' />