Say there are two arrays: 

```
String[] title = { "One","Two","three","Four"};
String[] user = { "rob","","john",""};

```

I need to filter out the above array when the `user` value is Empty then join or zip the two together. Final Output should be like: 

```
{ "One:rob", "three:john" } 

```

How can this be done using LINQ?