How to check array value and group them in php - php

Question

i have array:
Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 7 )
how to make condition in php when looping i can get output:
$datarange = 1-3,7;
i got logic like this:
if (value of array[0] + 1) = value of array[1] {
$datarange = value of array[0] - value of array[1];
}else{
$datarange = value of array[0] , value of array[1];
}
but i dont know how to Implement that to my looping

Answer 1

Here's a function that will make ranges when possible in an array of numbers.
<?php
function getRange($numbers) {
$lastNumber = null;
$currentRange = [];
$ranges = [];
foreach ($numbers as $number) {
if ($lastNumber === null) { // first iteration, add the number to current range
$currentRange[] = $number;
}
else {
if ($number - $lastNumber === 1) { // if difference with last number is 1, they're consecutive
$currentRange[] = $number;
}
else { // they're not consecutive, finish current range and start a new one
$ranges[] = $currentRange;
$currentRange = [$number];
}
}
$lastNumber = $number; // set the last number to compare with the next
}
$ranges[] = $currentRange; // add last range
$rangesString = []; //
foreach ($ranges as $range) {
$str = $range[0];
if (count($range) > 1) {
$str .= "-".$range[count($range) - 1];
}
$rangesString[] = $str;
}
return implode(", ", $rangesString);
}
echo getRange([1,2,3,7]); // result = 1-3, 7
echo getRange([1,2,6,9,10,12,15,17,18,19]); // result = 1-2, 6, 9-10, 12, 15, 17-19

Answer 2

Try this. I have change your logic and apply it in loop. for range:
$arr = array(1,2,3,7);
$last_val = "";
$first_val = "";
$add_val = true;
foreach ($arr as $key => $value) {
if($first_val == "")
$first_val = $value;
if(isset($arr[$key+1]))
{
if($value+1 == $arr[$key+1])
{
$last_val = $arr[$key+1];
$add_val = false;
}
else
$add_val = true;
}
else
$add_val = true;
if($add_val)
{
if($last_val != "")
$datarange[] = $first_val."-".$last_val;
else
$datarange[] = $first_val;
$first_val = "";
$last_val = "";
}
}
echo implode(",", $datarange);
DEMO