I am working with a one dimensional array in PHP. I would like to detect the presence of duplicate values, then count the number of duplicate values and output the results. For example, given the following array:
$array = [
'apple',
'orange',
'pear',
'banana',
'apple',
'pear',
'kiwi',
'kiwi',
'kiwi'
];
I would like to print:
apple (2)
orange
pear (2)
banana
kiwi (3)
Any advice on how to approach this problem?
You can use array_count_values function
$array = array('apple', 'orange', 'pear', 'banana', 'apple',
'pear', 'kiwi', 'kiwi', 'kiwi');
print_r(array_count_values($array));
will output
Array
(
[apple] => 2
[orange] => 1
[pear] => 2
etc...
)
if(count(array_unique($array))<count($array))
{
// Array has duplicates
}
else
{
// Array does not have duplicates
}
array_unique($array, SORT_REGULAR) forces PHP to check elements normally without changing the type, but it's a loose comparison. So different instances of one class with same content will be uniquified.function array_not_unique( $a = array() )
{
return array_diff_key( $a , array_unique( $a ) );
}
Result: (Demo)
array (
4 => 'apple',
5 => 'pear',
7 => 'kiwi',
8 => 'kiwi',
)
return array_values(array_unique(array_diff_key($a, array_unique($a))));You could try turning that array into a associative array with the fruits as keys and the number of occurrences as values. Bit long-winded, but it looks like:
$array = array('apple', 'orange', 'pear', 'banana', 'apple',
'pear', 'kiwi', 'kiwi', 'kiwi');
$new_array = array();
foreach ($array as $key => $value) {
if(isset($new_array[$value]))
$new_array[$value] += 1;
else
$new_array[$value] = 1;
}
foreach ($new_array as $fruit => $n) {
echo $fruit;
if($n > 1)
echo "($n)";
echo "<br />";
}
array_count_valuesTo get rid use array_unique(). To detect if have any use count(array_unique()) and compare to count($array).
Perhaps something like this (untested code but should give you an idea)?
$new = array();
foreach ($array as $value)
{
if (isset($new[$value]))
$new[$value]++;
else
$new[$value] = 1;
}
Then you'll get a new array with the values as keys and their value is the number of times they existed in the original array.
array_count_valuesStuff them into a map (pseudocode)
map[string -> int] $m
foreach($word in $array)
{
if(!$m.contains($word))
$m[$word] = 0;
$m[$word] += 1;
}
I didn't find the answer I was looking for, so I wrote this function. This will make an array that contains only the duplicates between the two arrays, but not print the number of times an element is duplicated, so it's not directly answering the question, but I'm hoping it'll help someone in my situation.
function findDuplicates($array1,$array2)
{
$combined = array_merge($array1,$array2);
$counted = array_count_values($combined);
$dupes = [];
$keys = array_keys($counted);
foreach ($keys as $key)
{
if ($counted[$key] > 1)
{$dupes[] = $key;}
}
sort($dupes);
return $dupes;
}
$array1 = [1,2,3,4,5];
$array2 = [4,5,6,7,8];
$dupes = findDuplicates($array1,$array2);
print_r($dupes);
Outputs:
Array
(
[0] => 4
[1] => 5
)
$data = ['outer', 'inner', 'sole', 'sole', 'outer', 'outer'];
$result = max(array_count_values($data));
if($result > 1) {
echo 'Duplicate items were found!';
}
I think this way is shorter and cleaner.
function array_not_unique(array $array): array
{
$duplicate_array = array_diff_key( $array , array_unique( $array ) );
$unique_array = [];
foreach ($array as $key => $value) {
if ( in_array($value, $duplicate_array)) {
$duplicate_array[$key] = $value;
}
else {
$unique_array[$key] = $value;
}
}
return ["unique_array" => $unique_array, "duplicate_array" => $duplicate_array];
}
This function give you the redundant values only
function array_find_redundant($A){
$U=$N=[];
foreach($A As $k=>$v){
if(in_array($v,$U)){$N[$k]=$v;}else{$U[]=$v;}
}
return $N;
}
$A = ['A','B','B','C','C','C'];
$B = array_find_redundant($A); // [2=>'B',4=>'C',5=>'C']
$arr = [1,2,2,2,4,5,5,5,8,9,10,2,5,9,10,10];
array_count_values($arr);
// OUT PUT Array(
// 2 => 4
// 5 => 4
// 9 => 2
// 10 => 3
// )
// If you want unique items
$items = array_keys( array_intersect( array_count_values($arr), [1] ) )
//If you want duplicate items
$duplicates = array_keys( array_diff( array_count_values($arr), [1] ) )
$count = 0;
$output ='';
$ischeckedvalueArray = array();
for ($i=0; $i < sizeof($array); $i++) {
$eachArrayValue = $array[$i];
if(! in_array($eachArrayValue, $ischeckedvalueArray)) {
for( $j=$i; $j < sizeof($array); $j++) {
if ($array[$j] === $eachArrayValue) {
$count++;
}
}
$ischeckedvalueArray[] = $eachArrayValue;
$output .= $eachArrayValue. " Repated ". $count."<br/>";
$count = 0;
}
}
echo $output;
Loop over the keys and values returned by array_count_values() and conditionally print the number of occurrences if greater than one.
Code: (Demo)
foreach (array_count_values($array) as $value => $count) {
printf("%s%s\n", $value, $count > 1 ? " ($count)" :'');
}
A simple method:
$array = array_values(array_unique($array, SORT_REGULAR));
