I have the following array:
$alphabet = array("a","b","c","d","e","f","g")
If I wanted to begin from "d" and loop through the array to be outputted as d,e,f,g,a,b,c.
How can this be achieved?
<?php
$alphabet = array("a","b","c","d","e","f","g");
$startIndex = 3;// index of d
$count = count($alphabet);
for($x = 0; $x < count($alphabet); $x++){
$index = $x + $startIndex < $count ? $x + $startIndex : $x + $startIndex - $count;
echo $alphabet[$index];
}
outputs
defgabc
see live demo
if you don't know the index of the element you want you can use array_search
$startIndex = array_search('d', $alphabet);
You can try to use array_slice function to achieve what you want:
<?php
$alphabet = array("a","b","c","d","e","f","g");
// find the index of the start element in the original array
$index = array_search("d", $alphabet);
// iterate the array from starting point to the end
foreach (array_slice($alphabet, $index) as $value) {
echo $value, ",";
}
// iterate the array from the very beginning to the starting point
foreach (array_slice($alphabet, 0, $index) as $value) {
echo $value, ",";
}
Related
i have a set of arrays:
$nums = array(2,3,1);
$data = array(11,22,33,44,55,66);
what i want to do is to get a set of $data array from each number of $nums array,
the output must be:
output:
2=11,22
3=33,44,55
1=66
what i tried so far is to slice the array and remove the sliced values from an array but i didn't get the correct output.
for ($i=0; $i < count($nums); $i++) {
$a = array_slice($data,0,$nums[$i]);
for ($x=0; $x < $nums[$i]; $x++) {
unset($data[0]);
}
}
Another alternative is to use another flavor array_splice, it basically takes the array based on the offset that you inputted. It already takes care of the unsetting part since it already removes the portion that you selected.
$out = array();
foreach ($nums as $n) {
$remove = array_splice($data, 0, $n);
$out[] = $remove;
echo $n . '=' . implode(',', $remove), "\n";
}
// since nums has 2, 3, 1, what it does is, each iteration, take 2, take 3, take 1
Sample Output
Also you could do an alternative and have no function usage at all. You'd need another loop though, just save / record the last index so that you know where to start the next num extraction:
$last = 0; // recorder
$cnt = count($data);
for ($i = 0; $i < count($nums); $i++) {
$n = $nums[$i];
echo $n . '=';
for ($h = 0; $h < $n; $h++) {
echo $data[$last] . ', ';
$last++;
}
echo "\n";
}
You can array_shift to remove the first element.
$nums = array(2,3,1);
$data = array(11,22,33,44,55,66);
foreach( $nums as $num ){
$t = array();
for ( $x = $num; $x>0; $x-- ) $t[] = array_shift($data);
echo $num . " = " . implode(",",$t) . "<br />";
}
This will result to:
2 = 11,22
3 = 33,44,55
1 = 66
This is the easiest and the simplest way,
<?php
$nums = array(2,3,1);
$data = array(11,22,33,44,55,66);
$startingPoint = 0;
echo "output:"."\n";
foreach($nums as $num){
$sliced_array = array_slice($data, $startingPoint, $num);
$startingPoint = $num;
echo $num."=".implode(",", $sliced_array)."\n";
}
?>
I have an associative array in PHP like this:
$weight["a"]=1;
$weight["b"]=4;
$weight["c"]=5;
$weight["d"]=9;
Here I want to calculate pair-wise difference between consecutive array elements, e.g.,
"b-a" = 3
"c-b" = 1
"d-c" = 4
How should this be computed?
Try this:
$i = 0;
foreach ($weight AS $curr) {
if ($i > 0) {
echo '"'.array_keys($weight)[$i].'-'.array_keys($weight)[$i-1].'" = '.($curr-$prev)."<br />";
}
$i++;
$prev = $curr;
}
Store keys on a temporary array where keys are integers on which you can easily get the next key, and use it to parse your main array.
$tmp_array = array();
foreach ($weight as $key => $val) {
$tmp_array[] = $key;
}
$array_length = count($tmp_array);
for ($i = 0; i < array_length - 2; ++$i) {
echo $weight[$tmp_array[$i+1]], '-', $weight[$tmp_array[$i]], ' = ', ($weight[$tmp_array[$i+1]] - $weight[$tmp_array[$i]], PHP_EOL;
}
I'll let the code speak:
$params = array();
$qtyCount = count(array(1,2,3,4,5));
$qtyAr = array(6,7,8,9,10);
$i = 1;
while($i <= $qtyCount){
$params['quantity_'.$i] .= $qtyAr[$i];
$i++;
}
But when I do this, the last value is missing.
BTW: the values in the qtyCount and qtyAr are bugus... just for example.
I would opt for a simpler approach:
array_walk($qtyAr, function($item, $index) use (&$params) {
$key = sprintf("quantity_%u", $index);
$params[$key] = $item;
});
It appears that you are starting at the wrong index (1), $i should be = 0 as others have pointed out.
You're missing the last element because your unasssociated array starts with 0 and your loop starts with 1. This is why foreach works so much better because it iterates over ALL your elements.
$qtyAr = array(6,7,8,9,10);
$i = 1;
foreach($qtyAr as $val) {
$params['quantity_' . $i] = $val;
$i++;
}
Let's say I have this array
$number = [2,1,4,3,6,2];
First pair the elements on an array by two's and find their difference
so this is the output in the first requirement
$diff[] = [1,1,4];
Second sum all the difference
this is the final output
$sum[] = [6];
Conditions:
the array size is always even
the first element in a pair is always greater than the second one, so their is no negative difference
What I've done so far is just counting the size of an array then after that I don't know how to pair them by two's. T_T
Is this possible in php? Is there a built in function to do it?
One line:
$number = [2,1,4,3,6,2];
$total = array_sum(array_map(function ($array) {
return current($array) - next($array);
}, array_chunk($number, 2)));
echo $total;
This should work fine:
<?
$number = array(2,1,4,3,6,2);
for($i=0;$i<count($number); $i+=2){
$dif[] = $number[$i] - $number[$i+1];
}
print_r($dif);
$sum = 0;
foreach ($dif as $item){
$sum += $item;
}
echo 'SUM = '.$sum;
?>
Working CODE
If you want all the different stages kept,
$numbers = [2,1,4,3,6,2];
$diff = [];
for($i=0,$c=count($numbers);$i<$c;$i+=2)
{
$diff[] = $numbers[$i]-$numbers[$i+1];
}
$sum = array_sum($diff);
Else, to just get the total and bypass the diff array:
$numbers = [2,1,4,3,6,2];
$total = 0;
for($i=0,$c=count($numbers);$i<$c;$i+=2)
{
$total += $numbers[$i]-$numbers[$i+1];
}
I have got this far it gives the required solution.
$arr = array(2,1,4,3,6,2);
$temp = 0;
$diff = array();
foreach ($arr as $key => $value) {
if($key % 2 == 0) {
$temp = $value;
}
else {
$diff[] = $temp - $value;
}
}
print_R($diff);
print 'Total :' . array_sum($diff);
Note : Please update if any one knows any pre-defined function than can sorten this code.
Please check and see if this works for you.
<?php
$sum=0;
$number = array(2,1,4,3,6,2);
for ($i=0;$i<=count($number);$i++) {
if ($i%2 == 1 ) {
$sum = $sum + $number[$i-1] - $number[$i];
}
}
print $sum;
?>
Well with your conditions in mind I came to the following
$number = [2,1,4,3,6,2];
$total = 0;
for($i = 0; $i < count($number); $i+=2) {
$total += $number[$i] - $number[$i + 1];
}
Try this one:
$number = array(2,1,4,3,6,2);
$diff = array();
$v3 = 0;
$i=1;
foreach($number as $val){
if ($i % 2 !== 0) {
$v1 = $val;
}
if ($i % 2 === 0) {
$v2 = $val;
$diff[] = $v1-$v2;
$v3+= $v1-$v2;
}
$i++;
}
print $v3;//total value
print_r($diff); //diff value array
I am trying to create a function which maps a recurring pattern of integers using an array.
As an example if I have a starting array of (0,1,3) and I know that I want to stop the pattern when I hit 15.
The pattern gets incremented by a fixed integer each time (lets say 4) so my final pattern should be..
0
1
3
4 (0 + 4)
5 (1 + 4)
7 (2 + 4)
8 (4 + 4)
9 (5 + 4)
11(7 + 4)
12(8 + 4)
13(9 + 4)
15(11+ 4)
Does anyone have any pointers on how this can be achieved?
My current implementation works but is stupidly inefficient which something like this...
$array = array(0,1,3);
$inc = 4;
$end = end($array);
$final = 15;
while($end < $final)
{
$tmp = array();
foreach($array AS $row)
{
$tmp = $row + $inc;
}
$array = merge($tmp, $array);
$end = end($array);
}
$array = array(0,1,3);
$inc = 4;
$final = 15;
$end = end($array);
while($end < $final)
{
$end += $inc;
$array[] = $end;
}
Or with a for loop:
$array = array(0,1,3);
$inc = 4;
$final = 15;
for($i = end($array) + $inc; $i <= $final; $i += $inc)
{
$array[] = $i;
}
Y'all are missing the fact that 4 is being added to the value in the array 2 keys back, not the last value.
This is the code you need (tested, and working)
$array = array(0,1,3);
$inc = 4;
$end = end($array);
$key = key($array);
$final = 15;
while ($end < $final) {
if ($array[$key-2] >= 0) {
$end = $array[$key-2] + $inc;
$array[] = $end;
$key++;
}
}
I also included in there a check to make sure the key being added to actually exists, though that may not be needed.
I assume that you want to have all the new values in the same array.
So:
//original array
$values = array(0, 1, 3);
//incremental value
$inc = 4;
//stop value
$stop = 15;
//set the index counter to the origin
$curr_index = 0;
//while the last value of the array is lower than the stop value
while($values[end($values)] < $stop)
{
//calculate the new value
$new_value = $values[$curr_index] + $inc;
//add the new value to the array
array_push($values, $new_value);
//update the index counter
$curr_index ++;
}
this code should work for any initial value in the array, any incremental value and any stop value.
<?php
function myArrayFunction(array $array, $inc = 4, $final = 15, $end = null)
{
if(!$end)
{
$end = end($array);
}
while($end < $final)
{
$end += $inc;
$array[] = $end;
}
return $array; //assume you're wanting $array back
}
This is minus any sort of testing or checking of injected values but you get the idea.
It would be better to know what you are trying to achieve here as the whole thing looks horribly overcomplicated, but...
$array = array(0,1,3);
$pattern = array();
$inc = 4;
$final = 15;
for ($base = 0; ; $base += $inc) {
foreach($array as $rem) {
if ($base + $rem > $final) break 2;
$pattern []= $base + $rem;
}
}
Alternatively,
$i = $v = 0;
while ($v < $final) {
$v = $pattern []= $pattern[$i++] + $inc;
}
(This assumes $final will be part of the pattern.)
If you can figure out how to calculate the number of elements will be in the array beforehand and assign that to $tum this should work.
<?php
$arr = array(0, 1, 3);
$inc = 4; // 6
$fin = 15; // 55
$num = count($arr);
$lum = 0;
$tum = 12; // 29
do
{
for($i = $lum; $i < $num; $i++)
{
$tar = $arr[$i] + $inc;
$arr[$tar] = $tar;
}
$lum = $num;
$num *= 2;
} while(end($arr) < $fin);
$arr = array_slice($arr, 0, $tum);
print_r($arr);
echo "\n";
?>