Sort a list, but leave a specified value in place
Locate and remove each of the values to ignore, remembering their positions.  For instance, in this case, you might store the index and value as ignore = (3, -1).
Sort the remaining list as usual.
Reinsert the missing element: mylist.insert(ignore[0], ignore[1])
Does that get you moving?
I need to use the numpy.argsort function (or a code that makes the same) but ignoring a concrete value, for example -1, and keeping it in the resulted array
If this is the list: [5,8,1,-1,2,4], I need a result like [3,4,0,-1,1,2]
How can I do it?