How can I separate from and to dates from dates array? - php

Question

I have an array, which has only one month dates.
$dates =array (
'2018-10-15',
'2018-10-16',
'2018-10-17',
'2018-10-13',
'2018-10-19',
'2018-10-10',
'2018-10-11',
'2018-10-12',
'2018-10-22',
'2018-10-23',
'2018-10-29',
);
And script below
usort($dates,function($a,$b){
return strtotime($a) - strtotime($b);
});
$consecutive_added_set = [];
$consecutive_array = [];
$temp = [];
$temp[] = date('Y-m-d',strtotime($dates[0]));
for($i=1;$i<count($dates);++$i){
if(strtotime($dates[$i]) - strtotime($dates[$i - 1]) === 86400){ // 1 day gap(86400 seconds)
$temp[] = date('Y-m-d',strtotime($dates[$i]));
$consecutive_added_set[$dates[$i-1]] = true;
$consecutive_added_set[$dates[$i]] = true;
}else{
if(count($temp) > 1){
$consecutive_array[] = $temp;
}
$temp = [];
$temp[] = date('Y-m-d',strtotime($dates[$i]));
}
}
if(count($temp) > 1){ // the last consecutiveness match of dates as well(corner case)
$consecutive_array[] = $temp;
}
$conseq[] = []; // reset the array structure
$conseq['consecutive'] = $consecutive_array;
$conseq['consecutive_count'] = count($consecutive_array);
$conseq['non_consecutive'] = [];
foreach($dates as $current_date){
if(!isset($consecutive_added_set[$current_date])){ // skip all dates which were d for consecutiveness
$conseq['non_consecutive'][] = date('Y-m-d',strtotime($current_date));
}
}
Which is sorting and separating consecutive and non-consective dates. Currently in consecutive array it is showing all dates by group. But I just would like to show from and to dates. Here is output of above script
Array
(
[0] => Array
(
)
[consecutive] => Array
(
[0] => Array
(
[0] => 2018-10-10
[1] => 2018-10-11
[2] => 2018-10-12
[3] => 2018-10-13
)
[1] => Array
(
[0] => 2018-10-15
[1] => 2018-10-16
[2] => 2018-10-17
)
[2] => Array
(
[0] => 2018-10-22
[1] => 2018-10-23
)
)
[consecutive_count] => 3
[non_consecutive] => Array
(
[0] => 2018-10-19
[1] => 2018-10-29
)
)
My desired output
[consecutive] => Array
(
['dates1'] => Array
(
[0] => 2018-10-10
[3] => 2018-10-13
)
['dates2'] => Array
(
[0] => 2018-10-15
[2] => 2018-10-17
)
['dates3'] => Array
(
[0] => 2018-10-22
[1] => 2018-10-23
)
)
I have tried a lot to do it.

Answer 1

A quick workaround would be to get the first and last item in the array.
$consecutive_array = array_map(function($e){
if(!is_array($e)){
return $e;
}
$last = end($e);
return [reset($e), $last];
}, $consecutive_array);
Or as suggested in the comments use min() max() functions.
$consecutive_array = array_map(function($e){
if(!is_array($e)){
return $e;
}
return [min($e), max($e)];
}, $consecutive_array);

Answer 2

Important: don't rely on strtodate of a day being exactly 86400 seconds less than the strtodate of the next day - depending on the locale of the server, there will be daylight saving, which can mess this up!
In cases like this, I tend to compare strtodate('+1 day',$timestampOfDay1) to strtodate($timestampOfDay2) - this will include daylight saving.
Here's how I would do it:
//the dates
$dates =array (
'2018-10-15',
'2018-10-16',
'2018-10-17',
'2018-10-13',
'2018-10-19',
'2018-10-10',
'2018-10-11',
'2018-10-12',
'2018-10-22',
'2018-10-23',
'2018-10-29',
);
//call the function
$result = getConsecutive($dates);
//output
var_dump($result);
function getConsecutive($dates) {
sort($dates);
$result = [
'consecutive' => [],
'consecutive_count'=>0,
'non_consecutive' => []
];
$currentStart = null;
$currentTimestamp = null;
for ($i=0; $i<count($dates); $i++) {
$timestamp = strtotime($dates[$i]);
if ($currentStart == null) {
//first timestamp - set it as start & current
$currentStart = $timestamp;
$currentTimestamp = $timestamp;
} else if (strtotime('+1 day',$currentTimestamp) == $timestamp) {
//consecutive - keep waiting for a non-consecutive
$currentTimestamp = $timestamp;
} else {
if ($currentTimestamp == $currentStart) {
//we just got one
$result['non_consecutive'][] = date('Y-m-d',$currentTimestamp);
} else {
//we just got more then one, so they were consecutive
$result['consecutive']['dates'.(count($result['consecutive'])+1)] = [
date('Y-m-d',$currentStart),
date('Y-m-d',$currentTimestamp)
];
}
$currentStart = $timestamp;
$currentTimestamp = $timestamp;
}
}
//process the last timestamp
if ($currentTimestamp == $currentStart) {
//we just got one
$result['non_consecutive'][] = date('Y-m-d',$currentTimestamp);
} else {
//we just got more then one, so they were consecutive
$result['consecutive']['dates'.(count($result['consecutive'])+1)] = [
date('Y-m-d',$currentStart),
date('Y-m-d',$currentTimestamp)
];
}
$result['consecutive_count'] = count($result['consecutive']);
return $result;
}