**Here I am Having an Issue:**

I have two arrays like the following:

```
  $array1 = array('1','2','1','3','1');
  $array2 = array('1','2','3'); // Unique $array1 values

```

with array2 values i need all keys of an array1

**Expected Output Is:**

```
 1 => 0,2,4
 2 => 1
 3 => 3

```

here it indicates `array2 value` =>`array1 keys`