Split php array to group when value is range or no - php

Question

I have array value like this :
$src = array(3,15,16,17,18,20,25,7);
How can i split it into :
array(
[0] => 3,
[1] => array([0] => 15, [1] => 18),//when value is range get start and end
[2] => 20,
[3] => 25,
[4] =>
);

Answer 1

Check this code. If your sequence/range difference is based on only next numbers, then this code would work for you.
<?php
$src = array(3,15,16,17,18,20,25,7);
$tot = count($src);
$resarr = array();
$st = $ed = '';
for($i=0;$i<$tot;$i++){
if($st==''){
if(isset($src[$i+1]) && $src[$i+1] == $src[$i]+1){
$st = $src[$i];
}
}
else{
if(!isset($src[$i+1]) || $src[$i+1] != $src[$i]+1){
$ed=$src[$i];
}
}
if($st=='' && $ed==''){
$resarr[] = $src[$i];
}
elseif($st!='' && $ed!=''){
$resarr[] = array($st,$ed);
$st = $ed='';
}
}
print_r($src);
echo "<pre>";print_r($resarr);echo "</pre>";
?>
Also phpfiddle example is here http://phpfiddle.org/lite/code/k7c4-wvdg. Keep practice write your own logic.

Answer 2

// Make copy of array with shifting to one item.
// And, to save array length, add one element to the end of the array.
// It can be any number, but not continue sequence.
// I add the last item of source array
$src1 = $src;
array_shift($src1);
array_push($src1,end($src));
// Then subtract corresponding items of array
$temp = array_map(function ($i, $j) { return $j-$i; }, $src, $src1);
// Look at arrays
// $src 3, 15, 16, 17, 18, 20, 25, 7
// $temp 12, 1, 1, 1, 2, 5, -18, 0,
// As you can see, all elements of sequences, but the last, has 1 in `temp` array.
// Therefore, we just need to collect the result
$sarr = false;
$result = array();
for($i=0; $i<count($src); $i++) {
if($temp[$i] == 1) {
if(! $sarr) {
$sarr = $src[$i];
}
}
else {
if(! $sarr) {
$result[] = $src[$i];
}
else {
$result[] = [$sarr, $src[$i]];
$sarr = false;
}
}
}
print_r($result);
Test it there

Answer 3

I added some values just to cover edge cases. Comments explain.
<?php
$src = array(3,4,15,16,17,18,20,25,7,8);
$res = [];
$start = null;
//Rather than make a counter use a for loop
for($i=0; $i < count($src); $i++){
//Make sure i+1 is not bigger than array
//If current index value + 1
//Euqals the next index value we have a range
if($i+1 < count($src) && $src[$i]+1 == $src[$i+1]){
if($start === null){
$start = $i;
}
//Once the range is over we can use the current index as end
} elseif($start !== null){
$res[] = array($src[$start], $src[$i]);
$start = null;
$end = null;
//There was never a range.
} else {
$res[] = $src[$i];
}
}
echo "<pre>";
print_r($res);
Results:
Array
(
[0] => Array
(
[0] => 3
[1] => 4
)
[1] => Array
(
[0] => 15
[1] => 18
)
[2] => 20
[3] => 25
[4] => Array
(
[0] => 7
[1] => 8
)
)