Remove consecutive array with duplicate values in multidimensional array using PHP - php

Question

I working on a function which filters a multi dimensional array, if the successive arrays have same value, I need to remove the arrays in between and get only the first and last of the successive arrays with duplicate values.
I cant figure out how to do this.
Hope you can help me.
Thanks.
SAMPLE CODE
function removeDuplicates($array){
$result = [];
$count = 0;
$firstValue = null;
for ($i = 0; $i < count($array); $i++) {
if($array[$i]['id'] == firstValue){
$result[] = $array[$i]);
}else{
// do action
}
}
return $array;
}
Sample Array
Array (
[0] => Array (
[key] => 0
[value] => 25
)
[1] => Array (
[key] => 1
[value] => 25
)
[2] => Array (
[key] => 2
[value] => 25
)
[3] => Array (
[key] => 3
[value] => 33
)
[4] => Array (
[key] => 4
[value] => 45
)
[5] => Array (
[key] => 5
[value] => 66
)
[6] => Array (
[key] => 6
[value] => 66
)
[7] => Array (
[key] => 7
[value] => 66
)
[8] => Array (
[key] => 8
[value] => 66
)
[9] => Array (
[key] => 9
[value] => 55
)
)
Here the first 3 arrays have same values (25), I need to remove the 2nd array and retain the 1st and 3rd, also with the 6th to 9th only retain the 6th and 9th array.
Expected Result
Array (
[0] => Array (
[key] => 0
[value] => 25
)
[2] => Array (
[key] => 2
[value] => 25
)
[3] => Array (
[key] => 3
[value] => 33
)
[4] => Array (
[key] => 4
[value] => 45
)
[5] => Array (
[key] => 5
[value] => 66
)
[8] => Array (
[key] => 8
[value] => 66
)
[9] => Array (
[key] => 9
[value] => 55
)
)

Answer 1

Try this:
$array = [
["key" => 0, "value" => 25],
["key" => 1, "value" => 25],
["key" => 2, "value" => 25],
["key" => 3, "value" => 33],
["key" => 4, "value" => 45],
["key" => 5, "value" => 66],
["key" => 6, "value" => 66],
["key" => 7, "value" => 66],
["key" => 8, "value" => 66],
["key" => 9, "value" => 55],
];
for ($i = 0; $i < count($array); $i++) {
if (!isset($array[$i])){
continue;
}
if ($array[$i]['value'] == $array[$i+1]['value']) {
$j = 1;
while ($array[$i]['value'] == $array[$i+$j+1]['value']) {
unset($array[$i+$j]);
$j += 1;
}
}
}
print_r($array);
Since you need to preserve the keys, for loop will throw a notice when an element is not set. This is why we first check if an element exists.
Then the loop looks for two identical values that are consecutive i.e. $i and $i+1. Once it finds them, it enters a while loop to test for 3 or more consecutive identical values. It will only unset a consecutive item if there is at least one occurrence before it and one after it. For example, it will delete $i+2 only if $i+3 is identical.
Hope this helps!

Answer 2

You can approach this as
$r = [];
$lastKey = '';
foreach($array as $k => $v){
if(in_array($v['value'], array_column($r, 'value'))){
$lastKey = $v['key'];
}else{
if($lastKey && !in_array($lastKey, array_column($r, 'key'))){
end($r);
$r[] = [ 'key' => $lastKey, 'value' => $r[key($r)]['value']];
}
$r[] = [ 'key' => $v['key'] , 'value' => $v['value'] ];
$lastKey = $v['key'];
}
}
https://3v4l.org/f6FQv

Answer 3

Here is the solution:
Your array is something like this:
$array = [
["key" => 0, "value" => 25],
["key" => 1, "value" => 25],
["key" => 2, "value" => 25],
["key" => 3, "value" => 33],
["key" => 4, "value" => 45],
["key" => 5, "value" => 66],
["key" => 6, "value" => 66],
["key" => 7, "value" => 66],
["key" => 8, "value" => 66],
["key" => 9, "value" => 55],
];
first, find the first and last occurrence of each value.
You need a method that travels through the array and find the exact value.
Look at this:
function search($search, $array)
{
foreach ($array as $key => $val) {
if ($val['value'] === $search) {
return $key;
}
}
return null;
}
Running $firstOccurrence = search(25, $array) will find the first occurrence of 25.
Now, for finding the index of the last occurrence, we should reverse array to traveling from the end of the array. So $lastOccurrence = search(25, array_reverse($array, true)) will find last occurrence index of 25.
Ok, When we process each value, so, We should not process it again. So we need an array which will hold values which are processed.
Final Code:
function testArray()
{
$array = [
["key" => 0, "value" => 25],
["key" => 1, "value" => 25],
["key" => 2, "value" => 25],
["key" => 3, "value" => 33],
["key" => 4, "value" => 45],
["key" => 5, "value" => 66],
["key" => 6, "value" => 66],
["key" => 7, "value" => 66],
["key" => 8, "value" => 66],
["key" => 9, "value" => 55],
];
$processedItems = [];
$newArray = [];
foreach ($array as $index => $item) {
if (in_array($item["value"], $processedItems))
continue;
$processedItems[] = $item["value"];
$firstIndex = search($item["value"], $array);
$lastIndex = search($item["value"], array_reverse($array, true));
$newArray[$firstIndex] = $array[$firstIndex];
if ($firstIndex != $lastIndex)
$newArray[$lastIndex] = $array[$lastIndex];
}
print_r($newArray);
}
function search($search, $array)
{
foreach ($array as $key => $val) {
if ($val['value'] === $search) {
return $key;
}
}
return null;
}

Answer 4

Please try this hope it's work
for ($i = 0; $i < count($array); $i++) {
if ($array[$i]['value'] == $array[$i+1]['value']) {
$j = 1;
while ($array[$i]['value'] == $array[$i+$j+1]['value']) {
echo $array[$i]['value'].'==='.$array[$i+$j+1]['value'];
unset($array[$i+$j]);
$j += 1;
}
}
}