PHP array_combine() function not working properly? - php

Question

I'm trying to combine two array in PHP with array_combine() function, but sometimes it working fine and sometimes it's not. I can't understand why it's working like this!
My Code:
var_dump($selectedDuretion);
var_dump($selectedDuretionType);
$combination = array_combine($selectedDuretion, $selectedDuretionType);
return $combination;
Expected OUTPUT:
array(4)
{
[0]=> string(1) "3"
[1]=> string(2) "12"
[2]=> string(1) "4"
[3]=> string(1) "3"
}
array(4)
{
[0]=> string(4) "days"
[1]=> string(4) "days"
[2]=> string(5) "weeks"
[3]=> string(5) "weeks"
}
{"3":"days","12":"days","3":"weeks","4":"weeks"}
Actual OUTPUT :
array(4)
{
[0]=> string(1) "3"
[1]=> string(2) "12"
[2]=> string(1) "4"
[3]=> string(1) "3"
}
array(4)
{
[0]=> string(4) "days"
[1]=> string(4) "days"
[2]=> string(5) "weeks"
[3]=> string(5) "weeks"
}
{"3":"weeks","12":"days","4":"weeks"}
The combination of arrays it shocking, I'll be thankful if anyone tell me why is this happening and how to solve it.

Answer 1

PHP Does not allow you to have duplicate indices in an array while JSON does allow you to have that for whatever reasons.
Since you are trying to convert PHP arrays to JSON your duplicate key gets eliminated. Hence you will have to manually build the JSON string.
$json="";
for($i=0;$i<count($selectedDuration);$i++)
{
$json.='"'.$selectedDuration[$i].'":"'.$selectedDurationType[$i].'",';
}
$json=rtrim($json,",");
$json="{".$json."}";
echo $json;
Output
{"3":"days","12":"days","4":"weeks","3":"weeks"}
Fiddle