php Get the original key value in in_array multidimensional - php

Question

I have a multidimensional array with some duplicate sub-arrays:
$data = array(
2 => array (
'User' => 'cat',
'File_name' => 'cat.docx',
'Document' => 'Document1',
'Date' => '2017-03-02',
'Pages' => 1
),
3 => array (
'User' => 'dog',
'File_name' => 'dog.docx',
'Document' => 'Document2',
'Date' => '2017-03-02',
'Pages' => 3
),
4 => array (
'User' => 'shark',
'File_name' => 'shark.docx',
'Document' => 'Document3',
'Date' => '2017-03-01',
'Pages' => 5
),
5 => array (
'User' => 'dog',
'File_name' => 'dog.docx',
'Document' => 'Document2',
'Date' => '2017-03-02',
'Pages' => 3
),
6 => array (
'User' => 'dog',
'File_name' => 'dog.docx',
'Document' => 'Document2',
'Date' => '2017-03-02',
'Pages' => 3
),
//...
);
I could recognize which items are duplicated with:
$final = $dupli = array();
foreach ($data as $key => $array ) {
if(!in_array($array, $final)){
$final[$key] = $array;
}
else
{
$dupli[$key] = $array;
}
}
print_r($dupli);
But I would like to know what index was the first subarray (the key of this) found, as a message, for example:
$final = $dupli = array();
foreach ($data as $key => $array ) {
if(!in_array($array, $final)){
$final[$key] = $array;
}
else
{
$dupli[$key] = $array;
echo "Line " . $key . " duplicated row, the original row is: " . $originalkey;
}
}
Output:
Line 5 duplicated row, the original row is: 3
Line 6 duplicated row, the original row is: 3

Answer 1

To find the key that has a specific value, you can use array_search().
So, to fetch the key from the final array, this should do it in your else statement:
$dupli[$key] = $array;
$originalkey = array_search($array, $final);
echo "Line " . $key . " duplicated row, the original row is: " . $originalkey . "\n";
Read more about array_search() in the docs

Answer 2

As Magnus Eriksson said you can use array_search, if you use it instead of in_array in your existing cycle you can do the operation only once per cycle:
$final = $dupli = array();
foreach ($data as $key => $array ) {
if(($originalkey = array_search($array, $final)) === false){
$final[$key] = $array;
}
else
{
$dupli[$key] = $array;
echo "Line " . $key . " duplicated row, the original row is: " . $originalkey;
}
}

Answer 3

Using array_search() along with loop you can simplify your code like below :
foreach($data as $index => $value)
{
$key = array_search($value, $data);
if($key!==false && $key != $index){
printf("Line %d duplicated row, the original row is: %d\n",$index, $key);
}
}
Test results on CLI
Script
akshay#db-3325:/tmp$ cat test.php
<?php
$data = array(
2 => array (
'User' => 'cat',
'File_name' => 'cat.docx',
'Document' => 'Document1',
'Date' => '2017-03-02',
'Pages' => 1
),
3 => array (
'User' => 'dog',
'File_name' => 'dog.docx',
'Document' => 'Document2',
'Date' => '2017-03-02',
'Pages' => 3
),
4 => array (
'User' => 'shark',
'File_name' => 'shark.docx',
'Document' => 'Document3',
'Date' => '2017-03-01',
'Pages' => 5
),
5 => array (
'User' => 'dog',
'File_name' => 'dog.docx',
'Document' => 'Document2',
'Date' => '2017-03-02',
'Pages' => 3
),
6 => array (
'User' => 'dog',
'File_name' => 'dog.docx',
'Document' => 'Document2',
'Date' => '2017-03-02',
'Pages' => 3
),
//...
);
foreach($data as $index => $value)
{
$key = array_search($value, $data);
if($key!==false && $key != $index){
printf("Line %d duplicated row, the original row is: %d\n",$index, $key);
}
}
?>
Output
akshay#db-3325:/tmp$ php test.php
Line 5 duplicated row, the original row is: 3
Line 6 duplicated row, the original row is: 3