Convert multidimensional array keys to string - php

Question

I have a multidimensional array like this:
$array1['first']='myvalue1';
$array1['second']=array();
$array1['second']['first']='myvalue21';
$array1['second']['second']='myvalue22';
$array1['second']['third']=array();
$array1['second']['third']['first']='myvalue231';
$array1['second']['fourth']='myvalue24';
$array1['third']='myvalue3';
And another array like:
$array2['second-first']='newvalue21';
$array2['second-third-first']='newvalue231';
And I can't get the way to walk $array1 recursively to check, in each iteration, if exist any element in $array2 with a key equivalent to the current element key and their parents converted to string.
To simplify the question, I will have enough with a function that prints something like:
// walking $array1:
first
second-first
second-second
second-third-first
second-fourth
third
Thank you.
Solution based on Clément Malet answer
function print_array_reccur ($array1, $array2, $str = '')
{
foreach ($array1 as $key => $val) {
if (is_array($val)) {
if ($str == '') {
print_array_reccur($val, $array2, $key);
} else {
print_array_reccur($val, $array2, $str . '-' . $key);
}
} else {
if ($str == '') {
$result = $key;
} else {
$result = $str . '-' . $key;
}
if(isset($array2[$result]))
{
echo 'Found $array2['.$result.'] = ' . $array2[$result] . "\n";
}
}
}
}
print_array_reccur ($array1, $array2);
/* OUTPUT:
Found $array2[second-first] = newvalue21
Found $array2[second-third-first] = newvalue231
*/

Answer 1

I really didn't understand what you wanted in the very end, and what you want to achieve later on with your second array.
But since you are looking for a way to print something (glad you simplified that way), here it is :
$array1['first']='myvalue1';
$array1['second']=array();
$array1['second']['first']='myvalue21';
$array1['second']['second']='myvalue22';
$array1['second']['third']=array();
$array1['second']['third']['first']='myvalue231';
$array1['second']['fourth']='myvalue24';
$array1['third']='myvalue3';
function print_array_reccur ($array, $str = '') {
foreach ($array as $key => $val) {
if (is_array($val)) {
if ($str == '') {
print_array_reccur($val, $key);
} else {
print_array_reccur($val, $str . '-' . $key);
}
} else {
if ($str == '') {
echo $key . "\n";
} else {
echo $str . '-' . $key . "\n";
}
}
}
}
print_array_reccur ($array1);
Output :
first
second-first
second-second
second-third-first
second-fourth
third