1 multidimensional array with 2 arrays inside merge the values - php

Question

i have a dynamically created multidimensional array with 2 arrays inside, but note it could also be 4 arrays inside. depends on the user.
The problem is that i dont know how to merge the values into 1 array because i only have 1 multidimensional array, i looked into array_merge but that requires 2 arrays. Please point me in the right direction.
it looks like this:
array (size=2)
'standaard' =>
array (size=4)
0 => float 0.42
1 => float 0.74
2 => float 0.39
3 => float 0.44
'natugro' =>
array (size=4)
0 => float 0.44
1 => float 0.8
2 => float 0.33
3 => float 0.36
What i want is to merge the 2 arrays values togetter in 1 array seperated with ':'
Like this:
array (size=1)
array (size=4)
0 => string '0.42:0.44' (length=4)
1 => string '0.74:0.8' (length=4)
2 => string '0.39:0.33' (length=4)
3 => string '0.44:0.36' (length=4)
What i tried:
but this only returns 1 array with the last values.
$test = array_merge($fruitHarvest);
var_dump($test);
This is the code that created the array.
$dbKenmerk = mysqli_query($conn, 'SELECT kenmerk FROM kenmerken WHERE user_id = '.$user.' AND jaar = '.$_SESSION["jaar"].'');
while($getKenmerk = mysqli_fetch_assoc($dbKenmerk)){
$dbFruitHarvest = mysqli_query($conn, 'SELECT vruchten_geoogst FROM gewasregistratie WHERE user_id = '.$user.' AND jaar = '.$_SESSION["jaar"].' AND kenmerk = "'.$getKenmerk["kenmerk"].'"');
foreach($dbFruitHarvest as $key => $innArr){
foreach($innArr as $val){
$fruitHarvest[$getKenmerk["kenmerk"]][] = $val;
}
}
}
var_dump($fruitHarvest);

Answer 1

This should work for you:
Just implode your elements with a colon.
<?php
array_unshift($fruitHarvest, function(){return implode(":", func_get_args());});
$result = call_user_func_array("array_map", $fruitHarvest);
print_r($result);
?>