Warm up

1) What happens when

>>> x = 1

is executed? The name “x” is assigned the value 1.

digraph first {
rankdir=LR;
one [label = "1", style=dotted, shape=polygon];
x [label="x", shape=circle];
x -> one;
}

2) Let’s take a look at

>>> x = 1
>>> y = x
>>> print(y)
1

The name “y” is assigned the value of the name “x”.

digraph first {
rankdir=LR;
one [label = "1", style=dotted, shape=polygon];
x [label="x", shape=circle];
y [label="y", shape=circle];
x -> one [weight=100];
y -> one;
}

Nothing special so far, just terminology.

Lessons

Fundamental facts behind values and names in Python:

Names cannot be assigned to another name.
Assignment never copies data.