Ian Mallett wrote:
If I have something like: x = [1,2,3,4,5,6] y = x then changes to y change x.
That's a rather loose way of talking about it. What's
happening is that x and y refer to the same object,
so any changes made to that object will be seen through
both x and y.
The important things to understand are:
(1) Python variables always contain references to objects,
not the objects themselves.
(2) The '=' operation is always reference assignment.
It never copies any objects.
y = [x[0],x[1],x[2],x[3],x[4],x[5]] ...which doesn't change x when y is changed.
Also
(3) The [...] notation always constructs a new list
object.
--
Greg