I’ve done this in code, but its ugly and probably very inefficient.

@hlship: I was trying this myself and would be interested to see your code (however ugly it may be )

Here is one way you could do it:

```
(remove element 1 namely $Head from [$Head | $Tail] leaving $Tail)
(remove element $N namely $Elem from [$Head | $TailIn] leaving [$Head | $TailOut])
($N minus 1 into $Nm1)
(remove element $Nm1 namely $Elem from $TailIn leaving $TailOut)
(shuffle [] into [])
(shuffle $Input into [$HeadOut | $TailOut])
(length of $Input into $N)
(random from 1 to $N into $I)
(remove element $I namely $HeadOut from $Input leaving $Rest)
(shuffle $Rest into $TailOut)
```

Now, it is somewhat inefficient to recompute the length of the list on every iteration, so you might want to define a helper predicate with an extra parameter:

```
(remove element 1 namely $Head from [$Head | $Tail] leaving $Tail)
(remove element $N namely $Elem from [$Head | $TailIn] leaving [$Head | $TailOut])
($N minus 1 into $Nm1)
(remove element $Nm1 namely $Elem from $TailIn leaving $TailOut)
(shuffle [] of length $ into [])
(shuffle $Input of length $N into [$HeadOut | $TailOut])
(random from 1 to $N into $I)
(remove element $I namely $HeadOut from $Input leaving $Rest)
($N minus 1 into $Nm1)
(shuffle $Rest of length $Nm1 into $TailOut)
(shuffle $Input into $Output)
(length of $Input into $N)
(shuffle $Input of length $N into $Output)
```

Hope this helps!

Hi Linus,

Is this code:

defined more thoroughly somewhere else, or is it just meant to be a starting point?

Thanks