How can I find the maximum and minimum date in an array? - php

Question

I need to find the maximum and minimum date from a given array using PHP.
I have $date_arr which contains following values,
$date_arr = array('0'=>'20-05-2015','1'=>'02-01-2015','2'=>'30-03-2015');
Here, I need to get the larger date as '20-05-2015' and the minimum date as '02-01-2015'.
How can I achieve this?

Answer 1

max() and min() works fine with your array:
echo "Latest Date: ". max($dates)."\n";
echo "Earliest Date: ". min($dates)."\n";

Answer 2

<?php
$date_arr=array(0=>'20-05-2015',1=>'02-01-2015',2=>'30-03-2015');
usort($date_arr, function($a, $b) {
$dateTimestamp1 = strtotime($a);
$dateTimestamp2 = strtotime($b);
return $dateTimestamp1 < $dateTimestamp2 ? -1: 1;
});
echo 'Min: ' . $date_arr[0];
echo '<br/>';
echo 'Max: ' . $date_arr[count($date_arr) - 1];
?>

Answer 3

please Try this
$date_arr = array('0' => '20-05-2015', '1' => '02-01-2015', '2' => '30-03-2015');
for ($i = 0; $i < count($date_arr); $i++)
{
if ($i == 0)
{
$max_date = date('Y-m-d H:i:s', strtotime($date_arr[$i]));
$min_date = date('Y-m-d H:i:s', strtotime($date_arr[$i]));
}
else if ($i != 0)
{
$new_date = date('Y-m-d H:i:s', strtotime($date_arr[$i]));
if ($new_date > $max_date)
{
$max_date = $new_date;
}
else if ($new_date < $min_date)
{
$min_date = $new_date;
}
}
}
echo date('d-m-Y',strtotime($max_date));
echo date('d-m-Y',strtotime($min_date));

Answer 4

Thought it doesn't technically offer the lowest computational time complexity, array_multisort() is a sensible, readable, concise approach. My snippet only calls strtotime() on each element once -- usort() cannot match this claim.
Code: (Demo)
$dates = ['20-05-2015', '02-01-2015', '30-03-2015', '10-01-1990'];
array_multisort(array_map('strtotime', $dates), $dates);
printf(
"Latest Date: %s\nEarliest Date: %s",
$dates[array_key_last($dates)],
$dates[0]
);
Output:
Latest Date: 10-01-1990
Earliest Date: 20-05-2015
To arrive at the same result by calling min() and max(), just create a formatted copy of the dates in unix time.
Code: (Demo)
$unix = array_map('strtotime', $dates);
printf(
"Latest Date: %s\nEarliest Date: %s",
date('d-m-Y', max($unix)),
date('d-m-Y', min($unix))
);
If you want to use usort(), here is the most modern syntax with the spaceship operator and arrow function syntax. (Demo)
usort($dates, fn($a, $b) => strtotime($a) <=> strtotime($b));
printf(
"Latest Date: %s\nEarliest Date: %s",
$dates[array_key_last($dates)],
$dates[0]
);
This task can surely be accomplished tens of different ways. I considered writing a foreach() loop with conditions to maintain temporary variables while making iterated comparisons, but I felt it was prohibitively convoluted for a rather simple task.

Answer 5

$date_arr=array(0=>'2015-05-20',1=>'2015-02-21',2=>'2015-04-13',3=>'2020-04-30',4=>'2020-04-13');
$max_date=$date_arr[0];
for($i=0;$i<count($date_arr);$i++)
{
echo $date_arr[$i]. ' ,';
if( $max_date < $date_arr[$i+1])
{
$max_date=$date_arr[$i+1];
}
}
echo " Max= ". $max_date;