Choose from dates array near date

Question

I have array

Array
(
    [0] => 2016-02-22 00:20:00
    [1] => 2016-02-25 08:45:00
    [2] => 2016-02-25 19:10:00
    [3] => 2016-02-25 20:00:00
    [4] => 2016-02-26 15:55:00
    [5] => 2016-02-28 17:10:00
)

How can i find which is nearest date from current date?

What means "nearest date"? Are dates in the past valid results? So that a date 5 minutes ago is "nearer" than a date 5 hours in the future? — maxhb, Feb 26 '16 at 12:58
Also please let us know what exactly you mean by "nearest". I mean please tell us whether you want to know a closest date that is less than current date or greater than current date or both. — Krishna Kumar N, Feb 26 '16 at 13:00
Who keeps upvoting badly specified questions like this, please stop it. — RiggsFolly, Feb 26 '16 at 13:01
[Here](http://stackoverflow.com/questions/15016725/how-to-get-closest-date-compared-to-an-array-of-dates-in-php) is similar question. — brevis, Feb 26 '16 at 13:02

score 2 · Accepted Answer · answered Feb 26 '16 at 13:04

//Start with your array
$array = ["2016-02-22 00:20:00", "2016-02-25 08:45:00", "2016-02-25 19:10:00", "2016-02-25 20:00:00", "2016-02-26 15:55:00", "2016-02-28 17:10:00", "2016-01-22 00:00:00"];

//Set an array called $closestTime that has the time difference and the key
$closestTime = [null,null];

//Check each element in array
foreach($array as $key => $date){

    //Calculate difference between now and the time in seconds
    $diff = strtotime("now") - strtotime($date);;
    if($diff<0) $diff = $diff * -1; 

    //If $closestTime is empty, populate it
    if($closestTime[0]===null) $closestTime = [$diff,$key];

    //If $closestTime isn't empty and the current date's time difference
    //is smaller, populate $closestTime with the time difference and key
    elseif($diff < $closestTime[0]) $closestTime = [$diff,$key];
}

//Print the closest time
echo $array[$closestTime[1]];

//Outputs:
//2016-02-26 15:55:00

score 1 · Answer 2 · answered Feb 26 '16 at 12:59

Easy: transform to timestamps, subtract the searched timestamp and take absolute value, find minimum.

Fast, assuming sorted array of timestamps: use binary search to find the first element that is larger, compare distance to that element with distance to previous element, pick one with smaller distance; if no element is larger, pick last element; if first element is already larger, pick first element.

Choose from dates array near date

2 Answers2