PHP - Delete all duplicates in array

Question

How can I delete duplicates from multiple arrays?

pinky and cocos are double in my array. All words which are double, must be removed. If those are removed, I will put these words in my select. I get those words from my database.

The query:

$queryClient = " SELECT DISTINCT `clients` FROM `reps` WHERE `clients` != ''";

This is my code:

while($row =  mysql_fetch_assoc($resultClient)){
    $names = explode(",", $row['clients']);
    echo '<pre>'; print_r($names); echo '</pre>';
}

Result: (Those food words are just an example)

Array
    (
        [0] => chocolate
    )
    Array
    (
        [0] => vanilla
        [0] => cocos
    )
    Array
    (
        [0] => strawberry
    )
    Array
    (
        [0] => pinky
        [1] => watermelon
        [2] => melon
        [3] => cocos
    )
    Array
    (
        [0] => pinky 
    )
    Array
    (
        [0] => dark-chocolate
    )

I tried this in my while loop but it did not work:

$array = array_unique($names, SORT_REGULAR);

How can I remove all duplicates? Can you help me or do you have a solution for my problem? Help.

i want a selector. the options of that selector is foods from my db **but** those wont be double — , Oct 24 '17 at 12:11
Ps. this will probably be _alot_ easier and cleaner to solve with a SQL query, so if you post that we can give you some pointers ;) Check out `GROUP BY` and the function `group_concat(DISTINCT field_name)` and similar :) — Richard87, Oct 24 '17 at 12:20
@Richard87 I think the root of the problem here is that the data is not normalised. — apokryfos, Oct 24 '17 at 12:57

u_mulder · Accepted Answer · 2017-10-24T13:50:33.700

4

Here's a one-liner:

print_r(array_unique(call_user_func_array('array_merge', $names)));

First merge all subarrays into one, then get unique values.

Full example:

$names = array();
while($row =  mysql_fetch_assoc($resultClient)){
    $names[] = explode(",", $row['clients']);
}
print_r(array_unique(call_user_func_array('array_merge', $names)));

edited Oct 24 '17 at 13:50

answered Oct 24 '17 at 12:13

u_mulder

54,101
5
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64

Sir, this does not work! Please help me! while($row = mysql_fetch_assoc($resultClient)){ $names = explode(",", $row['clients']); echo '
```
' . print_r(array_unique(call_user_func_array('array_merge', $names))).'
```
'; } @u_mulder
– Oct 24 '17 at 12:45
I understand you and this worked! but ... all of them needed to be **in** my select tag. I tried this but did not work: '.$names.''; } – Oct 24 '17 at 14:00
Do you __understand__ what you do in your code? Why do you assign result of `print_r` to `$cucul`? Do you know what `print_r` returns? – u_mulder Oct 24 '17 at 14:36

score 1 · Answer 2 · answered Oct 24 '17 at 12:14

You can just do a little trick:

Flatten, count and then remove all except the last.

$it = new RecursiveIteratorIterator(new RecursiveArrayIterator($array)); 
$flatArray = [];
foreach($it as $v) {
   $flatArray[] = $v;           //Flatten array
}

//Note you can do array_unique on the flat array if you also need to flatten the array

$counts = array_count_values($flatArray); //Count 

foreach ($array as &$subarray) {
     foreach ($subarray as $index => $element) {
          $counts[$element]--;
          if ($counts[$element] > 0) { //If there's more than 1 left remove it
               unset($subarray[$index]);
          }
     }
}

This will remove duplicates nested exactly on the 2nd level without flattening the original array.

http://sandbox.onlinephpfunctions.com/code/346fd868bc89f484dac48d12575d678f3cb53626

Richard87 · Answer 3 · 2017-10-24T12:31:14.700

1

first you need to join your array before you can filter out the duplicates:

<?php
$allNames = [];
while($row =  mysql_fetch_assoc($resultClient)){
    $names = explode(",", $row['food']);
    $allNames[] = $names;
}

$allNames = array_merge(...$allNames);  //Join everything to a one dimensional array
$allNames = array_unique($allNames); // Only keep unique elementes

print_r($allNames);

edited Oct 24 '17 at 12:31

answered Oct 24 '17 at 12:15

Richard87

1,592
3
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29

I tried your snippet, I get only one food word? strange isnt it? – Oct 24 '17 at 12:21
1

What about this snippet? A ***good answer*** will always have an explanation of what was done and why it was done in such a manner, not only for the OP but for future visitors to SO. – Jay Blanchard Oct 24 '17 at 12:30

PHP - Delete all duplicates in array

3 Answers3