I tried to solve this using a functional way, but I am not having much success. 

Suppose there is a list of lists, and it is required to pick only the lists in it which have unique entry in specific position.

For example, suppose there is a matrix, and we want to select only the rows which have unique elements in the first column.

Here is an example:

INPUT:

```
list= {{ 1,2}, {1,3},{4,5}}

```

I'd like the output to be

```
list={{1,2},{4,5}}

```

It does not matter which 'row' to remove, the first one is ok, but any one is fine.

I tried Select, DeleteCases, DeleteDuplicates, Union, and few other things, but can't get it to work. I do not know how to tell Mathematica to only look for 'unique' element. Union comes close but it works on complete list. i.e. I do not know what to write for criteria, as in

```
DeleteDuplicates[list, <now what?> ]

```

For reference, this is how I do the above in Matlab:

```
EDU>> A=[1 2;1 3;4 5]

A =
     1     2
     1     3
     4     5

EDU>> [B,I,J]=unique(A(:,1));
EDU>> A(I,:)

ans =
     1     3
     4     5

```

thanks