I want to merge / mix two arrays together, but I want it to be randomly "mixed" however NOT shuffled. For example:
$first = [1, 2, 3, 4];
$second = [10, 20, 30, 40];
Possible desired "mixes" are:
[1, 10, 20, 30, 2, 40, 3, 4][10, 1, 2, 20, 30, 3, 4, 40][1, 2, 3, 10, 20, 4, 30, 40]Note that if we pluck the values back out we would still have the original orders of:
1, 2, 3, 4
10, 20, 30, 40
Loop this script until both arrays are done.
$j = 0;
$i = 0;
$r = rand(0, 1);
if($r == 0) {
$ret .= $array1[$i];
$i++;
} elseif($r == 1) {
$ret .= $array2[$j];
$j++;
}
Of course, you have to handle a few exceptions in this code, but it might be the route.
Well, there's (yet another) one possible approach:
$arr = call_user_func_array('array_merge', array_map(null, $first, $second));
print_r($arr); // [1, 10, 2, 20, 3, 30, 4, 40];
Demo. That's apparently deterministic; for random ordering each pair should be shuffled additionally. For example:
function zipShuffle($first, $second) {
return call_user_func_array('array_merge', array_map(function($a, $b) {
return mt_rand(0, 1) ? [$a, $b] : [$b, $a];
}, $first, $second));
}
... but that obviously won't be able to churn out something like [1,2,3,10,20...]. If this is required, here's another solution:
function orderedShuffle($first, $second) {
$results = [];
$stor = [$first, $second];
$i = mt_rand(0, 1);
// switching between arrays on the fly
while (list(, $v) = each($stor[$i])) {
$results[] = $v;
$i = mt_rand(0, 1);
}
// one array is gone, now we need to add all the elements
// of the other one (as its counter left where it was)
$i = 1 - $i;
while (list(, $v) = each($stor[$i])) {
$results[] = $v;
}
return $results;
}
Demo. The last function is actually quite easy to extend for as many arrays as required.
Can you try this,
<?php
$first = array(1,2,3,4);
$second = array(10,20,30,40);
$arrayMixed=array();
$firstReverse=array_reverse($first);
$secondReverse=array_reverse($second);
$firstReverseCount = count($firstReverse);
$secondReverseCount = count($secondReverse);
foreach($firstReverse as $key=>$val) {
if ($firstReverseCount>0) {
array_push($arrayMixed, array_pop($firstReverse));
if ($secondReverseCount>0) {
array_push($arrayMixed, array_pop($secondReverse));
}
}
}
$ArrayMixeddata = array_merge($arrayMixed, $second);
echo "<pre>";
print_r($ArrayMixeddata);
echo "</pre>";
?>
Not quick ways, but them works.
// with permutations
function combineShuffleOrder($first, $second)
{
// combine into one array with alternation
$firstLen = count($first);
$secondLen = count($second);
$max = max($firstLen, $secondLen);
$result = array();
for($i=0; $i < $max; $i++) {
if ($i < $firstLen)
$result[] = $first[$i];
if ($i < $secondLen)
$result[] = $second[$i];
}
// "shuffle" with permutation
$len = count($result);
for($i=1; $i<$len; $i++) {
if (rand(1, 3) % 2 == 0) {
$tmp = $result[$i-1];
$result[$i-1] = $result[$i];
$result[$i] = $tmp;
$i++; // skip one exchange
}
}
return $result;
}
// with using "shuffle" in subarray
function combineShuffleOrder2($first, $second)
{
// combine into one array with alternation
$firstLen = count($first);
$secondLen = count($second);
$max = max($firstLen, $secondLen);
$result = array();
for($i=0; $i < $max; $i++) {
$sub = array();
if ($i < $firstLen)
$sub[] = $first[$i];
if ($i < $secondLen)
$sub[] = $second[$i];
shuffle($sub);
$result = array_merge($result, $sub);
}
return $result;
}
// with using "shuffle" in subarray if sources arrays are equals by length
function combineShuffleOrder3($first, $second)
{
$max = count($first);
$result = array();
for($i=0; $i < $max; $i++) {
$sub = array(
$first[$i],
$second[$i]
);
shuffle($sub);
$result = array_merge($result, $sub);
}
return $result;
}
$first = array(1,2,3,4);
$second = array(10,20,30,40);
print_r(combineShuffleOrder($first, $second));
print_r(combineShuffleOrder2($first, $second));
print_r(combineShuffleOrder3($first, $second));
I recommend forming a single array of the two input arrays for simpler toggling. Simply loop and consume one element from a randomly selected array and push that selection into the result array. When the pool of arrays is reduced to a single array, kill the loop and append the remaining elements of the last surviving array onto the result array.
I'll use a pool of four arrays (one which is empty from the beginning) to demonstrate that the snippet is robust enough to handle a variable number of arrays, a variable number of elements in each array, and empty arrays.
Code: (Demo)
$first = [1, 2, 3, 4];
$second = [10, 20, 30, 40];
$third = [];
$fourth = ['a', 'b'];
$pool = [$first, $second, $third, $fourth];
$result = [];
while (count($pool) > 1) {
$pullFrom = array_rand($pool);
if (!$pool[$pullFrom]) {
unset($pool[$pullFrom]);
continue;
}
$result[] = array_shift($pool[$pullFrom]);
}
var_export(array_merge($result, ...$pool));
Alternatively without array_merge() and count() calls, but it makes more iterated calls of array_shift(): (Demo)
$pool = [$first, $second, $third, $fourth];
$result = [];
while ($pool) {
$pullFrom = array_rand($pool);
if (!$pool[$pullFrom]) {
unset($pool[$pullFrom]);
continue;
}
$result[] = array_shift($pool[$pullFrom]);
}
var_export($result);