cs_disc_105

Q1 Mutability WWPD 10/5 Disc 06

x = [1,2,3]
x+=[4]
x = x+[4]

We see that x+=[4] does the same thing as

x.extend([4])

But the below:

x = x+[4]

Creates a new list and instead just assigns it to x.

• is and ==
  • == (equal value of list) -> checks if values of operands are equal. comparison operator
  • is -> checks if operand points to the same thing. identity operator
• copying lists
  • lis[:] creates a shallow copy of list, essentially just copying over the pointers to lists and other mutable elements contained within the outer list
• return value of .pop(i)

Iterators will continue to iterate through a list even if the list is being changed mid iteration