is and '==' i'm confused

[naughtyCat]

is is used to determine whether two variable reference objects are the same (same memory address)
== is used to determine whether the value of the reference variable is equal (same value but different memory address)

arr = [1, 2, 3]
a = arr # a is point to the same object with arr (means same memory address)
b = arr[:] # b is assigned the same value with arr

print(a is arr)
print(b is arr)

# Here you will find that arr and a have the same memory address but not b
print(id(arr))
print(id(a))
print(id(b))

Output:
True
False
1897473154560
1897473154560
1897476673216