convert lines to polyline (where endpoints coincide)

Hi, I have searched and (kinda) surprised I haven't found...

has anyone ever come across a LISP that once a line is selected will convert it and any touching lines (where the endpoints coincide) into a polyline?

In my case, they would be on a unique layer & colour etc, but there may be other lines on that layer (non-touching) that I would not want included in the selectionset

or.... is this an easy task?

Did you try the PEDIT command before you went in search for a lisp?

It does what you seem to be wanting.

To expand the solution:

• Call QSELECT and apply a proper filter to create a set including only the lines that were to be joined.
  
• Call PEDIT and input the Multiple mode; when asked to indicate the selection set for processing input Previous, then accept to convert them to polylines (if case) and choose Join.
  

As described by those above, this task could of course be completed using standard AutoCAD functionality.

To offer an alternative, you could use my Chain Selection program to obtain the initial selection, followed by my Polyline Join program (a simple wrapper for the PEDIT command) to convert the selection into a polyline.

.. something like this:

https://lispbox.wordpress.com/2017/04/30/unexplode-polylines/