Sorting PHP array without ksort - php

I am trying to manually sort a PHP array without making use of ksort.
This is how my code looks at the moment:
function my_ksort(&$arg){
foreach($arg as $key1 => $value1){
foreach($arg as $key2 => $value2){
if($key1 > $key2){
$aux = $value2;
$arg[$key2] = $value1;
$arg[$key1] = $aux;
}
}
}
}
It doesn't sort, I can't figure out how to make it sort.

You could try this:
function my_ksort(&$arg)
{
$keys=array_keys($arg);
sort($keys);
foreach($keys as $key)
{
$val=$arg[$key];
unset($arg[$key]);
$arg[$key]=$val;
}
}
I'm sorting the keys separately and then deleting the elements one-by-one and appending them to the end, in ascending order.
I'm using another sorting function (sort()), but if you want to eliminate all available sorting functions from your emulation, sort() is much easier to emulate. In fact, #crypticous's algorithm does just that!

This function return array in ASC. Take in consideration that I'm using goto which is supported in (PHP 5 >= 5.3.0)
function ascending_array($array){
if (!is_array($array)){
$array = explode(",", $array);
}
$new = array();
$flag = true;
iter:
$array = array_values($array); // recount array values with new offsets
(isset($min["max"])) ? $min["value"] = $min["max"] : $min["value"] = $array[0];
$min["offset"] = 0;
for ($i=0;$i<count($array);$i++){
if ($array[$i] < $min["value"]){ // redefine min values each time if statement executed
$min["value"] = $array[$i];
$min["offset"] = $i;
}
if ($flag){ // execute only first time
if ($array[$i] > $min["value"]){ // define max value from array
$min["max"] = $array[$i];
}
$flag = false;
}
if ($i === (count($array)-1)){ // last array element
array_push($new,$min["value"]);
unset($array[$min["offset"]]);
}
}
if (count($array)!=0){
goto iter;
}
print_r($new);
}
$arr = array(50,25,98,45);
ascending_array($arr); // 25 45 50 98
PS. When I was studying php, I wrote this function and now remembered that I had it (that's why I really don't remember what I am doing in it, though fact is it's working properly and hopefully there are comments too), hope you'll enjoy :)
DEMO

I was checking some issue related to this post and i wanted to give my insight about it ! here's what i would have done to implement php's sort :
$array_res = array();
$array = array(50,25,98,45);
$i=0;
$temp = $array[0];
$key = array_search($temp, $array);
while ($i<count($array)-1){
$temp = $array[0];
for($n=0;$n<count($array) ;$n++)
{
if($array[$n]< $temp && $array[$n] != -1 )
{
$temp = $array[$n];
}
else{continue;}
}
//get the index for later deletion
$key = array_search($temp, $array);
array_push($array_res, $temp);
/// flag on those which were ordered
$array[$key] =-1;
$i++;
}
// lastly append the highest number
for($n=0;$n<count($array) ;$n++)
{
if ($array[$n] != -1)
array_push($array_res, $array[$n]);
}
// display the results
print_r($array_res);
This code will display : Array
(
[0] => 25
[1] => 45
[2] => 50
[3] => 98
)

Short and sweet
function custom_ksort($arg)
{
$keys = array_keys($arg);
sort($keys);
foreach($keys as $newV)
{
$newArr[$newV] = $arg[$newV];
}
return $newArr;
}

It looks like your issue is that you're changing "temporary" characters $key1 and $key2 but not the actual arrays. You have to change $arg, not just $key1 and $key2.
Try something like:
$arr = Array(3=>"a",7=>"b");
print_r( $arr );
foreach( $arr as $k=>$v ){
unset($arr[$k]);
$arr[$k+1] = $v;
}
print_r($arr);

Related

Remove Duplicate Values from an array with ignoring last two characters

I am working on a small php script, currently i have an array like this
[0] yassine#m, [1] yassine#f, [2] Dolmi#m , [3] yassine#l
I want PHP to check if there is a duplicated element (yassine in this case) and return something like this.
[0] yassine , [1] Dolmi#m
array_unique won't work. And i really don't have any clue how to solve this. If looked for a solution on the internet but doesnt seem to find it. Anyone can help Please ?
I think this may work for you.
First sort array by value, then use combination of substr(), strpos() and array_push() to create new array according to your need
then remove duplicate value using array_unique()
<?php
$oldarray = array("suman#1","suman#2","suman#3","sujan#1","suresh#2","");
// first sort array by value so matching value comes together
asort($oldarray);
$newarray = array();
$count = count($oldarray);
for($i=0; $i < $count-1; $i++){
$a = $oldarray[$i];
$b = $oldarray[$i+1];
if($i == 0)
$c = "";
else
$c = $oldarray[$i-1];
if(substr($a,0,strpos($a,"#")) == substr($b,0,strpos($b,"#")) || substr($a,0,strpos($a,"#")) == substr($c,0,strpos($c,"#")) ){
array_push($newarray,substr($a,0,strpos($a,"#")));
}
else
array_push($newarray,$a);
}
print_r($oldarray);
// now remove duplicate value from new array
$newarray = array_unique($newarray);
print_r($newarray);
?>
Check following solution
http://ideone.com/fork/kJlLbs
<?php
function generateUniqueList ($arr){
$ret = array();
foreach ($arr as $value) {
$key = explode("#", $value)[0];
if (array_key_exists($key, $ret)) {
$ret[$key] = $key;
}
else {
$ret[$key] = $value;
}
}
return array_values($ret);
}
$arr = array("yassine#m","yassine#f","Dolmi#m", "yassine#l");
$list = generateUniqueList ($arr);
print_r($list);

Strip all elements from array where they occur less than twice

I have an array like this:
[0] = 2
[1] = 8
[2] = 7
[3] = 7
And I want to end up with an array that looks like:
[0] = 7
[1] = 7
Basically, remove all elements where they occur less than twice.
Is their a PHP function that can do this?
try this,
$ar1=array(2,3,4,7,7);
$ar2=array();
foreach (array_count_values($ar1) as $k => $v) {
if ($v > 1) {
for($i=0;$i<$v;$i++)
{
$ar2[] = $k;
}
}
}
print_r($ar2);
output
Array ( [0] => 7 [1] => 7 )
Something like this would work, although you could probably improve it with array_reduce and an anonymous function
<?php
$originalArray = array(2, 8, 7, 7);
foreach (array_count_values($originalArray) as $k => $v) {
if ($v < 2) {
$originalKey = array_search($k, $originalArray);
unset($originalArray[$originalKey]);
}
}
var_dump(array_values($originalArray));
$testData = array(2,8,7,7,5,6,6,6,9,1);
$newArray = array();
array_walk(
array_filter(
array_count_values($testData),
function ($value) {
return ($value > 1);
}
),
function($counter, $key) use (&$newArray) {
$newArray = array_merge($newArray,array_fill(0,$counter,$key));
}
);
var_dump($newArray);
Though it'll give a strict standards warning. To avoid that, you'd need an interim stage:
$testData = array(2,8,7,7,5,6,6,6,9,1);
$newArray = array();
$interim = array_filter(
array_count_values($testData),
function ($value) {
return ($value > 1);
}
);
array_walk(
$interim,
function($counter, $key) use (&$newArray) {
$newArray = array_merge($newArray,array_fill(0,$counter,$key));
}
);
var_dump($newArray);
You could use a combination of array_count_values (which will give you an associative array with the value as the key, and the times it occurs as the value), followed by a simple loop, as follows:
$frequency = array_count_values($yourArray);
foreach ($yourArray as $k => $v) {
if (!empty($frequency[$v]) && $frequency[$v] < 2) {
unset($yourArray[$k]);
}
}
I did not test it, but I reckon it works out of the box. Please note that you will loop over your results twice and not N^2 times, unlike an array_search method. This can be further improved, and this is left as an exercise for the reader.
This was actually harder to do than i thought...anyway...
$input = array(2, 8, 7, 7, 9, 9, 10, 10);
$output = array();
foreach(array_count_values($input) as $key => $value) {
if ($value > 1) $output = array_merge($output, array_fill(0, $value, $key));
}
var_dump($output);
$arrMultipleValues = array('2','3','5','7','7','8','2','9','11','4','2','5','6','1');
function array_not_unique($input)
{
$duplicatesValues = array();
foreach ($input as $k => $v)
{
if($v>1)
{
$arrayIndex=count($duplicatesValues);
array_push($duplicatesValues,array_fill($arrayIndex, $v, $k));
}
}
return $duplicatesValues;
}
$countMultipleValue = array_count_values($arrMultipleValues);
print_r(array_not_unique($countMultipleValue));
Is their [sic!] a PHP function that can do this?
No, PHP has no built-in function (yet) that can do this out of the box.
That means, if you are looking for a function that does this, it needs to be in PHP userland. I would like to quote a comment under your question which already suggest you how you can do that if you are looking for that instead:
array_count_values() followed by a filter with the count >1 followed by an array_fill() might work
By Mark Baker 5 mins ago
If this sounds a bit cryptic to you, those functions he names are actually built-in function in PHP, so I assume this comes most close to the no, but answer:
array_count_values()
array_fill()
This does the job, maybe not the most efficient way. I'm new to PHP myself :)
<?php
$element = array();
$element[0] = 2;
$element[1] = 8;
$element[2] = 7;
$element[3] = 7;
$count = array_count_values($element);
var_dump($element);
var_dump($count);
$it = new RecursiveIteratorIterator( new RecursiveArrayIterator($count));
$result = array();
foreach ($it as $key=>$val){
if ($val >= 2){
for($i = 1; $i <= $val; $i++){
array_push($result,$key);
}
}
}
var_dump($result);
?>
EDIT: var_dump is just so you can see what's going on at each stage

php remove value from array

Hi I need help in removing values from an array using a recursive function
$array = [0] => testing,testing1
[1] => testing,testing1,testing2
[2] => testing,testing1,testing2,testing3
[3] => testing,testing1,testing2,testing3,tesing4
[4] => testing,testing1,testing2,testing3,tesing4
[5] => testing,testing1,testing2,testing3,tesing4
[6] => testing,testing1,testing2,testing3,tesing4
[7] => testing,testing1,testing2,testing3,tesing4
I need to check the array count, ie if count(array[0]) == count(array[1]),then reutrn array
else unset(array[value]);
From the above array I have to remove array[0],[1],[2] and return rest of the array values.
I've tried the below code
$idx =10;
$separtor =',';
function array_delete($idx, $array,$separtor) {
$finalvalue = array();
for ($i = 0; $i < $idx; $i++) {
$values = explode($separtor, $array[$i]);
$valuesnext = explode($separtor, $array[$i+1]);
if(count($values) != count($valuesnext) )
{
unset($array[$i]);
// reset($array);
// array_delete($idx, $array,$separtor);
if (is_array($array)) $array = array_delete($idx, $array,$separtor);
$finalvalue = $array;
}else
{
}
//echo $i;
}
return $finalvalue;
//(is_array($array)) ? array_values($array) : null;
//array_delete($idx, $array,$separtor);
}
I'm getting Notice: Undefined offset: 0 when trying calling recursive, going to infinite loop
Do you want to keep the sub-arrays that have the most items? Your descriptions appear to say this.
If so, something like the following would suffice.
// Get maximum number of items in the arrays
$max_count = max(array_map('count', $array));
// Keep only those arrays having $max_count items
$filtered = array_filter($array, function ($a) use ($max_count) {
return count($a) === $max_count;
});
Aside: if you need the filtered array to have zero-based keys, call array_values() on it.
See an example running online.
If I understand correctly, you want to filter the array such that any value in the final array is of the same length as the last element in the source array. In order to avoid mutating an array while iterating over it, this technique builds a fresh array with the elements that match your criteria.
$matchLength = count($mainArray[count($mainArray) - 1]);
$resultArray = array();
for($i = 0; $i < count($mainArray); $i++) {
if(count($mainArray[$i]) == $matchLength) {
$resultArray[] = $mainArray[$i];
}
}
If you happen to be using PHP 5.3 or greater, you can do this quicker with closures and array_filter:
$matchLength = count($mainArray[count($mainArray) - 1]);
$resultArray = array_filter($mainArray, function($element){return count($element) == $matchLength});
Double check the code, I haven't been writing PHP lately, so this is just an idea.
According to the description you gave, it could be just made (check the count of the current and the provious one, if they don't match, remove the previous one).
Example/Demo:
unset($prevKey);
$count = array();
foreach (array_keys($array) as $key) {
$count[$key] = count($array[$key]);
if (isset($prevKey) && $count[$prevKey] !== $count[$key]) {
unset($array[$prevKey]);
}
$prevKey = $key;
}
If you need to re-iterate to take removals into account, a little goto can do the job Demo:
start:
######
unset($prevKey);
$count = array();
foreach (array_keys($array) as $key) {
$count[$key] = count($array[$key]);
if (isset($prevKey) && $count[$prevKey] !== $count[$key]) {
unset($array[$prevKey]);
goto start;
###########
}
$prevKey = $key;
}

Removing array item by value [duplicate]

This question already has answers here:
PHP: How to remove specific element from an array?
(22 answers)
PHP array delete by value (not key)
(20 answers)
Closed 1 year ago.
I need to remove array item with given value:
if (in_array($id, $items)) {
$items = array_flip($items);
unset($items[ $id ]);
$items = array_flip($items);
}
Could it be done in shorter (more efficient) way?
It can be accomplished with a simple one-liner.
Having this array:
$arr = array('nice_item', 'remove_me', 'another_liked_item', 'remove_me_also');
You can do:
$arr = array_diff($arr, array('remove_me', 'remove_me_also'));
And the value of $arr will be:
array('nice_item', 'another_liked_item')
I am adding a second answer. I wrote a quick benchmarking script to try various methods here.
$arr = array(0 => 123456);
for($i = 1; $i < 500000; $i++) {
$arr[$i] = rand(0,PHP_INT_MAX);
}
shuffle($arr);
$arr2 = $arr;
$arr3 = $arr;
/**
* Method 1 - array_search()
*/
$start = microtime(true);
while(($key = array_search(123456,$arr)) !== false) {
unset($arr[$key]);
}
echo count($arr). ' left, in '.(microtime(true) - $start).' seconds<BR>';
/**
* Method 2 - basic loop
*/
$start = microtime(true);
foreach($arr2 as $k => $v) {
if ($v == 123456) {
unset($arr2[$k]);
}
}
echo count($arr2). 'left, in '.(microtime(true) - $start).' seconds<BR>';
/**
* Method 3 - array_keys() with search parameter
*/
$start = microtime(true);
$keys = array_keys($arr3,123456);
foreach($keys as $k) {
unset($arr3[$k]);
}
echo count($arr3). 'left, in '.(microtime(true) - $start).' seconds<BR>';
The third method, array_keys() with the optional search parameter specified, seems to be by far the best method. Output example:
499999 left, in 0.090957164764404 seconds
499999left, in 0.43156313896179 seconds
499999left, in 0.028877019882202 seconds
Judging by this, the solution I would use then would be:
$keysToRemove = array_keys($items,$id);
foreach($keysToRemove as $k) {
unset($items[$k]);
}
How about:
if (($key = array_search($id, $items)) !== false) unset($items[$key]);
or for multiple values:
while(($key = array_search($id, $items)) !== false) {
unset($items[$key]);
}
This would prevent key loss as well, which is a side effect of array_flip().
to remove $rm_val from $arr
unset($arr[array_search($rm_val, $arr)]);
The most powerful solution would be using array_filter, which allows you to define your own filtering function.
But some might say it's a bit overkill, in your situation...
A simple foreach loop to go trough the array and remove the item you don't want should be enough.
Something like this, in your case, should probably do the trick :
foreach ($items as $key => $value) {
if ($value == $id) {
unset($items[$key]);
// If you know you only have one line to remove, you can decomment the next line, to stop looping
//break;
}
}
Try array_search()
Your solutions only work if you have unique values in your array
See:
<?php
$trans = array("a" => 1, "b" => 1, "c" => 2);
$trans = array_flip($trans);
print_r($trans);
?>
A better way would be unset with array_search, in a loop if neccessary.
w/o flip:
<?php
foreach ($items as $key => $value) {
if ($id === $value) {
unset($items[$key]);
}
}
function deleteValyeFromArray($array,$value)
{
foreach($array as $key=>$val)
{
if($val == $value)
{
unset($array[$key]);
}
}
return $array;
}
You can use array_splice function for this operation Ref : array_splice
array_splice($array, array_search(58, $array ), 1);

Checking if array is multidimensional or not?

What is the most efficient way to check if an array is a flat array
of primitive values or if it is a multidimensional array?
Is there any way to do this without actually looping through an
array and running is_array() on each of its elements?
Use count() twice; one time in default mode and one time in recursive mode. If the values match, the array is not multidimensional, as a multidimensional array would have a higher recursive count.
if (count($array) == count($array, COUNT_RECURSIVE))
{
echo 'array is not multidimensional';
}
else
{
echo 'array is multidimensional';
}
This option second value mode was added in PHP 4.2.0. From the PHP Docs:
If the optional mode parameter is set to COUNT_RECURSIVE (or 1), count() will recursively count the array. This is particularly useful for counting all the elements of a multidimensional array. count() does not detect infinite recursion.
However this method does not detect array(array()).
The short answer is no you can't do it without at least looping implicitly if the 'second dimension' could be anywhere. If it has to be in the first item, you'd just do
is_array($arr[0]);
But, the most efficient general way I could find is to use a foreach loop on the array, shortcircuiting whenever a hit is found (at least the implicit loop is better than the straight for()):
$ more multi.php
<?php
$a = array(1 => 'a',2 => 'b',3 => array(1,2,3));
$b = array(1 => 'a',2 => 'b');
$c = array(1 => 'a',2 => 'b','foo' => array(1,array(2)));
function is_multi($a) {
$rv = array_filter($a,'is_array');
if(count($rv)>0) return true;
return false;
}
function is_multi2($a) {
foreach ($a as $v) {
if (is_array($v)) return true;
}
return false;
}
function is_multi3($a) {
$c = count($a);
for ($i=0;$i<$c;$i++) {
if (is_array($a[$i])) return true;
}
return false;
}
$iters = 500000;
$time = microtime(true);
for ($i = 0; $i < $iters; $i++) {
is_multi($a);
is_multi($b);
is_multi($c);
}
$end = microtime(true);
echo "is_multi took ".($end-$time)." seconds in $iters times\n";
$time = microtime(true);
for ($i = 0; $i < $iters; $i++) {
is_multi2($a);
is_multi2($b);
is_multi2($c);
}
$end = microtime(true);
echo "is_multi2 took ".($end-$time)." seconds in $iters times\n";
$time = microtime(true);
for ($i = 0; $i < $iters; $i++) {
is_multi3($a);
is_multi3($b);
is_multi3($c);
}
$end = microtime(true);
echo "is_multi3 took ".($end-$time)." seconds in $iters times\n";
?>
$ php multi.php
is_multi took 7.53565130424 seconds in 500000 times
is_multi2 took 4.56964588165 seconds in 500000 times
is_multi3 took 9.01706600189 seconds in 500000 times
Implicit looping, but we can't shortcircuit as soon as a match is found...
$ more multi.php
<?php
$a = array(1 => 'a',2 => 'b',3 => array(1,2,3));
$b = array(1 => 'a',2 => 'b');
function is_multi($a) {
$rv = array_filter($a,'is_array');
if(count($rv)>0) return true;
return false;
}
var_dump(is_multi($a));
var_dump(is_multi($b));
?>
$ php multi.php
bool(true)
bool(false)
For PHP 4.2.0 or newer:
function is_multi($array) {
return (count($array) != count($array, 1));
}
I think this is the most straight forward way and it's state-of-the-art:
function is_multidimensional(array $array) {
return count($array) !== count($array, COUNT_RECURSIVE);
}
After PHP 7 you could simply do:
public function is_multi(array $array):bool
{
return is_array($array[array_key_first($array)]);
}
You could look check is_array() on the first element, under the assumption that if the first element of an array is an array, then the rest of them are too.
I think you will find that this function is the simplest, most efficient, and fastest way.
function isMultiArray($a){
foreach($a as $v) if(is_array($v)) return TRUE;
return FALSE;
}
You can test it like this:
$a = array(1 => 'a',2 => 'b',3 => array(1,2,3));
$b = array(1 => 'a',2 => 'b');
echo isMultiArray($a) ? 'is multi':'is not multi';
echo '<br />';
echo isMultiArray($b) ? 'is multi':'is not multi';
Don't use COUNT_RECURSIVE
click this site for know why
use rsort and then use isset
function is_multi_array( $arr ) {
rsort( $arr );
return isset( $arr[0] ) && is_array( $arr[0] );
}
//Usage
var_dump( is_multi_array( $some_array ) );
Even this works
is_array(current($array));
If false its a single dimension array if true its a multi dimension array.
current will give you the first element of your array and check if the first element is an array or not by is_array function.
You can also do a simple check like this:
$array = array('yo'=>'dream', 'mydear'=> array('anotherYo'=>'dream'));
$array1 = array('yo'=>'dream', 'mydear'=> 'not_array');
function is_multi_dimensional($array){
$flag = 0;
while(list($k,$value)=each($array)){
if(is_array($value))
$flag = 1;
}
return $flag;
}
echo is_multi_dimensional($array); // returns 1
echo is_multi_dimensional($array1); // returns 0
I think this one is classy (props to another user I don't know his username):
static public function isMulti($array)
{
$result = array_unique(array_map("gettype",$array));
return count($result) == 1 && array_shift($result) == "array";
}
In my case. I stuck in vary strange condition.
1st case = array("data"=> "name");
2nd case = array("data"=> array("name"=>"username","fname"=>"fname"));
But if data has array instead of value then sizeof() or count() function not work for this condition. Then i create custom function to check.
If first index of array have value then it return "only value"
But if index have array instead of value then it return "has array"
I use this way
function is_multi($a) {
foreach ($a as $v) {
if (is_array($v))
{
return "has array";
break;
}
break;
}
return 'only value';
}
Special thanks to Vinko Vrsalovic
Its as simple as
$isMulti = !empty(array_filter($array, function($e) {
return is_array($e);
}));
This function will return int number of array dimensions (stolen from here).
function countdim($array)
{
if (is_array(reset($array)))
$return = countdim(reset($array)) + 1;
else
$return = 1;
return $return;
}
Try as follows
if (count($arrayList) != count($arrayList, COUNT_RECURSIVE))
{
echo 'arrayList is multidimensional';
}else{
echo 'arrayList is no multidimensional';
}
$is_multi_array = array_reduce(array_keys($arr), function ($carry, $key) use ($arr) { return $carry && is_array($arr[$key]); }, true);
Here is a nice one liner. It iterates over every key to check if the value at that key is an array. This will ensure true

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