In python I have two list with non-unique values:
a = [1,2,3,4,5,5,4,3,2,1,2,3,4,5]
b = [1,2,2,2,5,5]
To substract b from a
I found solution:
from collections import Counter as mset
subtract = mset(a) - mset(b)
list(subtract.elements())
#result is [1, 3, 3, 3, 4, 4, 4, 5]!!!!!!!!
How to do the same in PHP? PHP does not support lists.
array_diff is not useful, because it deletes non-unique values
A "functional" solution:
$a = [1,2,3,4,5,5,4,3,2,1,2,3,4,5];
$b = [1,2,2,2,5,5];
$bCopy = $b;
$c = array_filter($a, function($item) use(&$bCopy) {
$idx = array_search($item, $bCopy);
// remove it from $b if found
if($idx !== false) unset($bCopy[$idx]);
// keep the item if not found
return $idx === false;
});
sort($c);
print_r($c);
You will need to make a copy of $b as the array_filter callback is destructive in regards to the array $b. Also you will need to sort the result if you want to have exact the same output as in python.
Related answers:
#1
#2
For the example you provided, you can try the following:
$a = [1,2,3,4,5,5,4,3,2,1,2,3,4,5];
var_dump($a);
$b = [1,2,2,2,5,5];
var_dump($b);
$c = array_diff($a, $b);
var_dump($c);
It should give you the following result:
array (size=14)
0 => int 1
1 => int 2
2 => int 3
3 => int 4
4 => int 5
5 => int 5
6 => int 4
7 => int 3
8 => int 2
9 => int 1
10 => int 2
11 => int 3
12 => int 4
13 => int 5
array (size=6)
0 => int 1
1 => int 2
2 => int 2
3 => int 2
4 => int 5
5 => int 5
array (size=6)
2 => int 3
3 => int 4
6 => int 4
7 => int 3
11 => int 3
12 => int 4
Update
Found the answer here.
I wrapped the solution in a useful function:
function array_diff_duplicates($array1, $array2) {
$counts = array_count_values($array2);
$result = array_filter($array1, function($o) use (&$counts) {
return empty($counts[$o]) || !$counts[$o]--;
});
sort($result, SORT_NUMERIC);
return $result;
}
Trying the following:
$a = [1,2,3,4,5,5,4,3,2,1,2,3,4,5];
$b = [1,2,2,2,5,5];
$c = array_diff_duplicates($a, $b);
var_dump($c);
Gives the expected result:
array (size=8)
0 => int 1
1 => int 3
2 => int 3
3 => int 3
4 => int 4
5 => int 4
6 => int 4
7 => int 5
Related
I have a site with a search feature but am trying to improve the search for a fuzzy search.
So far what I've done is query all of my products and use similar_text() to see how close they are to the actual search term
I then create an array where the key is how similar it is and the value is the product id. I then sort this by the key/similarity.
$term = $_GET['search_term'];
$similar_array = [];
$sql = "SELECT * FROM products";
$stmt = DB::run($sql);
while ($row = $stmt->fetch(PDO::FETCH_ASSOC)){
$id = $row["pro_id"];
$result = $row['product'];
similar_text($term,$result,$similarity);
$similar_array[$similarity][] = $id;
}
$closest_match = array_keys($similar_array);
rsort($closest_match);
$match_count = count($closest_match);
for($i=0; $i<$match_count; $i++){
var_dump($similar_array[$closest_match[$i]]);
}
This gives me something like:
array (size=9)
0 => int 28
1 => int 1628
2 => int 1665
3 => int 1666
4 => int 1667
5 => int 1668
6 => int 1669
7 => int 1670
8 => int 1671
C:\wamp64\www\V2\search.php:65:
array (size=2)
0 => int 37
1 => int 38
C:\wamp64\www\V2\search.php:65:
array (size=1)
0 => int 481
C:\wamp64\www\V2\search.php:65:
array (size=3)
0 => int 27
1 => int 1009
2 => int 1620
C:\wamp64\www\V2\search.php:65:
array (size=14)
0 => int 30
1 => int 104
2 => int 131
3 => int 134
4 => int 168
5 => int 169
6 => int 170
7 => int 557
8 => int 1011
9 => int 1014
10 => int 1661
11 => int 1662
12 => int 1663
13 => int 1664
I have a show_products() function that I just need to pass an array of ID's, so what I want to do now is take the multiple arrays of ID's from above and merge it in this specific order and then crop the array to a certain number so it won't have every product but will cut off after so many results.
As per your query you can use follow below steps
you merge all array by array_merge
sort the array using rsort (highest merge come first);
for display you can use array_slice or array_chunk
to be precise I have:
$foo = [1, 4, 1, 5, 8, 1, 3, 5, 1, 4, 1, 3, 7, 2];
sort($foo);
$bar = array_count_values($foo);
for ($i = 1; $i < count($bar); $i++) {
if (!isset($bar[$i])) {
$bar[$i] = 0;
}
}
Actual result:
array (size=8)
1 => int 5
2 => int 1
3 => int 2
4 => int 2
5 => int 2
7 => int 1
8 => int 1
6 => int 0
Expected result:
array (size=8)
1 => int 5
2 => int 1
3 => int 2
4 => int 2
5 => int 2
6 => int 0
7 => int 1
8 => int 1
Why my key value pair 6 => 0 appears in the bottom of an array instead of a specific place?
It's because you are appending a new value to the array.
To "fix" that, use ksort($bar);.
As #Rob Ruchte wrote in comments, the array returned by array_count_values() is associative, which means there is no order with the keys.
http://php.net/manual/en/function.array-count-values.php
Returns an associative array of values from array as keys and their count as value.
I have an array like this one:
array (size=1)
0 =>
array (size=33)
0 => int 126
1 => int 43
2 => int 4
3 => int 0
4 => int 3
5 => int 3
6 => int 30
7 => int 15
8 => int 22
9 => int 27
10 => int 22
11 => int 46
12 => int 0
13 => int 8
14 => int 14
15 => int 8
array (size=1)
1 =>
array (size=33)
0 => int 273
1 => int 3
2 => int 4
3 => int 28
4 => int 36
5 => int 19
6 => int 142
7 => int 81
8 => int 59
9 => int 71
10 => int 88
11 => int 47
12 => int 42
13 => int 0
14 => int 12
15 => int 97
(of course it is way longer)
and I need both to sum all the value with the same key and count how many values with the same key are >0 (cause I have to find the avarage of all the numbers >0
My expected result is
0=>
'sum' => 399
'count'=>2
1=>
'sum' =>46
'count'=>2
how can I create this array?
There's an inbuilt function in PHP to count the sum of all the elements of an array. Here, this will give you your expected output :
<?php
$arr = [[10, 20, 30, 40], [10, 20, 30], [10, 20, 30, 4]];
// Let the magic happen...
$yourArray = array_map(function ($el){ return ["sum" => array_sum($el), "count" => count($el)]; }, $arr);
print_r($yourArray);
?>
I have thought about this, and came up with a solution (I think...), it comes in the form of a function and it goes like this:
function getSumAndCount(array $arr)
{
$sum = 0;
$count = 0;
foreach ($arr as $v)
{
$count++;
if (is_array($v))
{
$next = getSumAndCount($v);
$count += $next['count'];
$sum += $next['sum'];
}
else
{
!is_numeric($v) ?: $sum += $v;
}
}
return [ 'sum' => $sum, 'count' => $count ];
}
It has a recursive check to if the array is multidimensional, checks if the value is numeric and sets the count and sum in a return array.
I haven't tested this properly as yet, but please test and let me know if you get the desired output.
EDIT
I will extend this to count dupe keys soon
I'm using PHP on foreach function
$arr = array(array(1,2,3,4,5,6,7,8,9,10));
foreach($arr as $item){
var_dump($item);
}
And here is my result
array (size=10)
0 => int 1
1 => int 2
2 => int 3
3 => int 4
4 => int 5
5 => int 6
6 => int 7
7 => int 8
8 => int 9
9 => int 10
But I want to revers from high to small back
array (size=10)
0 => int 10
1 => int 9
2 => int 8
3 => int 7
4 => int 8
5 => int 9
6 => int 4
7 => int 5
8 => int 2
9 => int 1
How can I do
Use array_reverse() :
$arr = array(array(1,2,3,4,5,6,7,8,9,10));
foreach($arr as $item){
var_dump(array_reverse ($item));
}
See result
You could use PHPs reverse array sort (rsort). See the Documentation
$arr = array(array(1,2,3,4,5,6,7,8,9,10));
rsort($arr);
foreach($arr as $item){
var_dump($item);
}
This question already has answers here:
How to have a stable sort in PHP with arsort()?
(7 answers)
Closed 9 years ago.
There is strange issue in php asort, arsort.
I am taking example of arsort
Case1
$a = array(
1 => 2,
2 => 1,
3 => 2,
4 => 1
);
arsort($a);
var_dump($a);
Output:
array(4) {
[3] =>
int(2)
[1] =>
int(2)
[4] =>
int(1)
[2] =>
int(1)
}
Here at index (3,1) and (4,2) are sorted in descending order because at index 3 and 1 values are same. Same for index 4 and 2.
Case2
$a = array(
1 => 2,
2 => 1,
3 => 2
);
arsort($a);
var_dump($a);
Output:
array(3) {
[1] =>
int(2)
[3] =>
int(2)
[2] =>
int(1)
}
Here at index (3,1) are sorted in ascending order and still at index 3 and 1 values are same.
Is there any solution for this issue? As I want that ordering should be certain. Like sort in either descending or ascending order if value at some indices are same.
According to the PHP documentation:
If any of these sort functions evaluates two members as equal then the order is undefined (the sorting is not stable).
You can't know exactly which behaviour is correct, with testing just with 2 elements. Here's an array with multiple elements (odd and even).
even number:
<?php
$a = array(
1 => 2,
2 => 1,
3 => 2,
4 => 1,
5 => 2,
6 => 1,
7 => 2,
8 => 1,
9 => 2,
10 => 1,
11 => 2,
12 => 1
);
arsort($a);
var_dump($a);
Result:
array (size=12)
1 => int 2
7 => int 2
5 => int 2
11 => int 2
9 => int 2
3 => int 2
10 => int 1
12 => int 1
6 => int 1
2 => int 1
4 => int 1
8 => int 1
odd number
<?php
$a = array(
1 => 2,
2 => 1,
3 => 2,
4 => 1,
5 => 2,
6 => 1,
7 => 2,
8 => 1,
9 => 2,
10 => 1,
11 => 2,
12 => 1,
13 => 2
);
arsort($a);
var_dump($a);
Result
array (size=13)
9 => int 2
11 => int 2
13 => int 2
1 => int 2
7 => int 2
3 => int 2
5 => int 2
12 => int 1
2 => int 1
4 => int 1
8 => int 1
6 => int 1
10 => int 1
The question is now, where did it add the 13th element (=2)? it's added just after the 11th element and before the first element...this means that there's no rule here. (At least according to what we see).
We can't say that it follows any rule with testing with just 2 variables like what you did, because you saw (1,3) and you presumed that it's sorted by key. Which is apparently not the case with multiple variables.