I am trying to split an array of items into multiple equal parts with a maximum of 6 items per array
for example:
5 items in original array --> result: 1 array with 5 items
12 items in original array --> result: 2 arrays with 6 items
7 items in original array --> result: 2 arrays with 3 and 4 items
13 items in original array --> result: 3 arrays with 5,4,4 items
I have absolutely no idea how to get started on this
I guess this is what you are looking for. Not exactly beautiful, but working:
<?php
$size = 13;
$step = 6;
$input = array_keys(array_fill(0, $size, null));
$count = ceil($size / $step);
$chunk = floor($size / $count);
$bonus = $size % $count;
for ($i = 0; $i < $count; $i++) {
$output[] =
$i == 0 ?
array_slice($input, $i * $chunk, $chunk + $bonus) :
array_slice($input, $i * $chunk + $bonus, $chunk);
}
print_r($output);
Here $size is the size of your array and $step is the size of the chunks cut from that array. You can play around with those values.
An example output with the settings above would be:
Array
(
[0] => Array
(
[0] => 0
[1] => 1
[2] => 2
[3] => 3
[4] => 4
)
[1] => Array
(
[0] => 5
[1] => 6
[2] => 7
[3] => 8
)
[2] => Array
(
[0] => 9
[1] => 10
[2] => 11
[3] => 12
)
)
Ok, I did this with a more dynamic programming way, where in we compute the distribution for smaller subproblems and go from 6 to 1, to see if current $j in the code fits in any of the previous distribution.
<?php
$arr = [];
$size = rand(1,150);
$range = range(1,$size);
$dist = [];
$dist[] = [];
for($i=1;$i<=$size;++$i){
if($i <= 6) $dist[] = [$i];
else{
for($j=6;$j>=1;--$j){
if(abs($j - $dist[$i-$j][0]) <= 1){
$dist[] = array_merge($dist[$i-$j],[$j]);
break;
}
}
}
}
// echo $size,PHP_EOL;
// print_r($dist[$size]); print the distribution if you want.
$result = [];
$curr_index = 0;
foreach($dist[$size] as $chunk_size){
$result[] = array_slice($range,$curr_index,$chunk_size);
$curr_index += $chunk_size;
}
echo $size,PHP_EOL;
print_r($result);
Demo: https://3v4l.org/gCWB2 (Note that the output there is different for each version of PHP as a different random number of an array size is generated each time).
Update: You can further optimize the above code for this heavy line $dist[] = array_merge($dist[$i-$j],[$j]);, but this I leave as an exercise to you(hint: store only the smallest starting one with it's count).
I'm trying to fill an array with a for loop. This is done to get the amount of pages a certain book has. but when executing the code, it skips the first object in the array. Can anyone tell me why? (I thought it was because $i starts at 1 instead of 0 but that doesn't seem to change anything)
if(!empty($article['finishing'])){
$numPages = $article['copies'];
$arrayIndexNumber = [];
for($i=1; $i <= $numPages; $i++){
$arrayIndexNumber[] = $i;
}
if(count($arrayIndexNumber) >= 1 ){
if(count($arrayIndexNumber) == 1){
$output['attributes']['EFPageRange'] = 1;
$print_jobs[$article['id']][] = $output;
}
if(count($arrayIndexNumber) > 1){
$comma_separated1 = implode(", ", ['1', $article['copies']]);
$output['attributes']['EFPageRange'] = $comma_separated1;
$print_jobs[$article['id']][] = $output;
}
array_shift($arrayIndexNumber);
array_pop($arrayIndexNumber);
$comma_separated2 = implode(", ", $arrayIndexNumber);
$output['attributes']['EFPageRange'] = $comma_separated2;
if(count($arrayIndexNumber) >= 2){
$print_jobs[$article['id']][] = $output;
}
}
$article['file_url'] = 'i has finishing';
$output['attributes']['username'] = $article['file_url'];
}
above code outputs:
[0] => Array
(
[attributes] => Array
(
[title] => 277569
[EFPrintSize] => a4
[num copies] => 1
[num pages] => 119
[EFPCName] => 80
[EFDuplex] => TopTop
[EFPageRange] => 1, 119
)
)
instead of:
[0] => Array
(
[attributes] => Array
(
[title] => 277564
[EFPrintSize] => a4
[num copies] => 1
[num pages] => 45
[EFPCName] => 80
[EFDuplex] => false
[EFPageRange] => 1, 45
[username] => i has finishing
[EFColorMode] => Grayscale
)
)
Your first array element is deleted because of array_shift:
array_shift($arrayIndexNumber);
array_shift
array_shift — Shift an element off
the beginning of array
Debug your code:
for($i=1; $i <= $numPages; $i++){
$arrayIndexNumber[] = $i;
}
echo '<pre>';
print_r($arrayIndexNumber); // Check what the array returns
php array indexes starts to count from zero
for($i=1; $i <= $numPages; $i++)
^^^
change it to $i=0
Below is a part of my produced array. How can I keep only every second element usign PHP?
I have tried this until now without luck, maybe it depends on the structure of the array, I didn't understand.
$size = count($array);
$result = array();
for ($i = 0; $i < $size; $i += 2) {
$result[] = $array[$i];
}
var_dump($result);
this is my array below:
Array
(
[0] => Array
(
[0] =>
11.490
[1] =>
11.490
[2] =>
13.490
[3] =>
13.490
[4] =>
17.490
[5] =>
17.490
[6] =>
20.990
[7] =>
20.990
[8] =>
14.290
[9] =>
14.290
[10] =>
14.490
[11] =>
14.490
[12] =>
19.990
[13] =>
19.990
Use array_filter (php.net)
function odd($var)
{
return($var & 1);
}
$array[0] = array_filter($array[0], "odd", ARRAY_FILTER_USE_KEY);
EDIT:
Of course you can also use an "even" method
EDIT 2:
Change to match the code from the op.
From $array to $array[0]
EDIT 3:
Add a missing semicolon
How about using unset on every other element?
<?php
$array = array('1','1','2','2','4','4','5','5');
for($i = count($array) - 1; $i > 0; $i -= 2){
unset($array[$i]);
}
Hi i am trying to create a sub array from an array.i.e; think I have an array such as given below
$array = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19}
which I explode and assign it to a variable $i..
and run the for loop as shown below..
for ( $i=0;$i<count($array);$i++) {
$a = array();
$b = $array[$i];
for($j=0;$j<count($array);$j++){
if($b != $array[$j]){
$a[] = $array[$j];
}
}
the output I want is when
$i = 1
the array should be
{2,3,4,5,6,7,8,9,10,11}
and when
$i = 2
the array should be
{3,4,5,6,7,8,9,10,11,12}
similarly when
$i=19
the array should be
{1,2,3,4,5,6,7,8,9,10}
so how can I do it.
Assuming $i is supposed to be an offset and not the actual value in the array, you can do
$fullArray = range(1, 19);
$i = 19;
$valuesToReturn = 10;
$subset = iterator_to_array(
new LimitIterator(
new InfiniteIterator(
new ArrayIterator($fullArray)
),
$i,
$valuesToReturn
)
);
print_r($subset);
This will give your desired output, e.g.
$i = 1 will give 2 to 11
$i = 2 will give 3 to 12
…
$i = 10 will give 11 to 1
$i = 11 will give 12 to 2
…
$i = 19 will give 1 to 10
$i = 20 will give the same as $i = 1 again
and so on.
$array = range(1, 19);
$i = 19;
$result = array();
$after = array_slice($array, $i, 10);
$before = array_slice($array, 0, 10 - count($after));
$result = array_merge($after, $before);
var_dump(json_encode($result));
P.S. please note 0 element has 1 value and so on...
for ($i = 0; $i < count($array); $i++) {
if ($i + 10 < count($array))
$a = array_slice($array, $i, 10);
else
$a = array_merge(array_slice($array, $i), array_slice($array, 0, 10-(count($array)-$i)));
// do something with $a before it is over-written on the next iteration
}
This test:
<?php
$array = array(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19);
for ($i = 0; $i < count($array); $i++) {
if ($i + 10 < count($array))
$a = array_slice($array, $i, 10);
else
$a = array_merge(array_slice($array, $i), array_slice($array, 0, 10-(count($array)-$i)));
echo "<h2>$i</h2>\n<pre>".print_r($a,true)."</pre><br />\n";
}
Resulted in this:
0
Array
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
[4] => 5
[5] => 6
[6] => 7
[7] => 8
[8] => 9
[9] => 10
)
...
9
Array
(
[0] => 10
[1] => 11
[2] => 12
[3] => 13
[4] => 14
[5] => 15
[6] => 16
[7] => 17
[8] => 18
[9] => 19
)
10
Array
(
[0] => 11
[1] => 12
[2] => 13
[3] => 14
[4] => 15
[5] => 16
[6] => 17
[7] => 18
[8] => 19
[9] => 1
)
...
18
Array
(
[0] => 19
[1] => 1
[2] => 2
[3] => 3
[4] => 4
[5] => 5
[6] => 6
[7] => 7
[8] => 8
[9] => 9
)
This works fine from my end
<?php
$array = array(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19);
$size = sizeof($array); // Defining the array size
$str = 17; // This is the reference value from which you have to extract the values
$key = array_search($str, $array);
$key = $key+1; // in order to skip the given reference value
$start = $key%$size;
$end = $start+9;
for($i=$start; $i<=$end; $i++) {
$j = ($i%$size);
$result[] = $array[$j];
}
echo '<pre>'; print_r($result);
?>
It looks like all you need is a slice of a certain size from the array, slice that wraps around the array's end and continues from the beginning. It treats the array like a circular list.
You can achieve this in many ways, one of the simplest (in terms of lines of code) is to extend the original array by appending a copy of it at its end and use the PHP function array_slice() to extract the slice you need:
function getWrappedSlice(array $array, $start, $count = 10)
{
return array_slice(array_merge($array, $array), $start, $count);
}
Of course, you have to be sure that $start is between 0 and count($array) - 1 (including), otherwise the value returned by the function won't be what you expect.
Round-robin on an array can be achieved by doing a "rotate" operation inside each iteration:
for ($i = 0; $i < count($array); ++$i) {
// rotate the array (left)
array_push($array, array_shift($array));
// use $array
}
During the loop, the first element of the array is placed at the back. At the end of the loop, the array is restored to its original value.
Let's say I have following array:
Array
(
[0] => Array
(
[0] => a
[1] => 1
)
[1] => Array
(
[0] => b
[1] => 8
)
[2] => Array
(
[0] => c
[1] => 16
)
[3] => Array
(
[0] => d
[1] => 21
)
....
)
Numbers in inner array are generated randomly from range (0, 100) and they don't repeat.
I would like to create a loop, which will iterate from 0 to 100 and check if loop iteration is equal to inner number of above array. Excepted result is array with 100 elements:
Array
(
[0] => const
[1] => a
[2] => const
[3] => const
[4] => const
[5] => const
[6] => const
[7] => const
[8] => b
[9] => const
[10] => const
.
.
[16] => c
[17] => const
.
.
[21] => d
[22] => const
[23] => const
.
.
)
What I need is something like:
for ($i=0; $i < 100; $i++) {
if($i === $name[$i][1]) {
$new_array[] = $name[$i][0];
} else {
$new_array[] = 'const';
}
}
But I can't get it working, thus I need some help.
I am not an English native speaker, so hopefully you understand what I would like to achieve. Thanks for any help.
you need a nested loop like:
for ($i=0; $i < 100; $i++):
$found = false;
foreach($name as $array):
if($array[1] === $i):
$found = true;
$new_array[] = $array[0];
endif;
endforeach;
if(!$found):
$new_array[] = 'const';
endif;
endfor;
The reason it doesn't work is because each time $i is incremented you're trying to make a match in $name[$i], and not checking all of the arrays in $name, the simplest solution I can think of (and to perform the least number of iterations) would be to do something like:
$new_array = array();
foreach ($name as $n) {
$new_array[$n[1]] = $n[0];
}
for ($i=0; $i<100; $i++) {
if (!isset($new_array[$i])) {
$new_array[$i] = 'const';
}
}
ksort($new_array);
So first of all, loop through your $name array, and set up your $new_array with the the key => value pair (eg. [1] => 'a', [8] => 'b'), then in the for loop just check if the key ($i) has already been set, and if not, set it with the value 'const'. Finally, sort the $new_array by its keys.
The number of iterations in this example is count($name) + 100, whereas a nested loop for example would be 100 * count($name).
use
for ($i=0; $i < 100; $i++) {
if($i === $name[$i][1]) {
$new_array[$i] = $name[$i][0];
}
else{
$new_array[$i] = 'const';
}
}
for ($i = 0; $i < count($name); ++$i) {
if ($name[$i][1] === $i) {
$name[$i] = $name[$i][0];
} else {
$name[$i] = 'const';
}
}
Why do u use Identical operator instead of Equal
for ($i=0; $i < 100; $i++) {
if($i == $name[$i][1]) {
$new_array[] = $name[$i][0];
} else {
$new_array[] = 'const';
}
}