List mutability
===============

#. Which is the value of list ``a`` after each of these assignment statements ?

   .. code:: python

       a = [['a', 1], 3, [4, 5, 'b'], [1, [2, 'c'], 9]]
       a[0] = 5.7
       a[-1] = 'hello'
       a[1] = ['X', 1, 2.5]
       a[0:2] = [0, 1]
       a[2:4] = []
       a[0:1] = [2, 3, 4, 5]
       a[1:1] = ['x', 'y']
       a[-2:] = ['a', 'b', 'c']
       a[:-5] = [0, 1, 2]
       a[15:20] = [5, 6]

#. List ``a`` has been defined as follows:

   .. code:: python

       a = ['a', 'b', 'c', 'd', 'e', 'f']

   write assignment statements to match the following expressions:

   .. code:: python

       a == ['a', 'b', 1, 'd', 'e', 'f']
       a == ['a', 'b', 'c', 'd', 2, 3]
       a == ['a', 'e', 'f']
       a == ['a', 'b', 'c', 'd', 4, 5, 'e', 'f']
       a == [6, 'c', 'd', 'e', 'f']
       a == ['a', 'b', 'c', 7]
       a == ['a', 8, 9, 'f']
       a == ['a', 'b', 'c', 'd', 'e', 'f', 10, 11, 12]


#. Which is the value of list ``b`` after the execution of each of the
   following assignment statements ?:

   .. code:: python

       b = ['garlic', 'onion', 'parsley']
       del b[0]
       b[0] = 'thyme'
       b[0] = ['garlic', 'onion', 'rosemary']
       b[0:1] =['garlic', 'onion']
       b =  b + b

#. We have written the two following Python functions

   .. code:: python

       def list_test1(w):
           w = [1,1,1,1]
           w[1] = 5
     
       def list_test2(w):
           w[1] = 5
           w = [1,1,1,1]

   What will the value of variables k1 and k2 be after executing the
   following instructions ?

   .. code:: python

       >>> k1 = [0,0,0]
       >>> k2 = [0,0,0]
       >>> list_test1(k1)
       >>> list_test2(k2)

   Give a reasoned answer. You can check the result using the following
   test file:  :download:`mutab.txt <mutab.txt>`

#. After executing these assignment statements:

   .. code:: python

       a = ['a', 5, [], 3.2, [4, 'bc']]
       b = ['a', 5, [], 3.2, [4, 'bc']]

   have ``a`` and ``b`` the same value? Are they the same object ?
   You can check it by using the operators ``==`` and ``is``, respectively.

#. After executing these assignment statements:

   .. code:: python

       a = ['a', 5, [], 3.2, [4, 'bc']]
       b = a

   have ``a`` and ``b`` the same value? Are they the same object ?
   You can check it by using the operators ``==`` and ``is``, respectively.

#. After executing these assignment statements:

   .. code:: python

       a = ['a', 5, [], 3.2, [4, 'bc']]
       b = a[:]

   have ``a`` and ``b`` the same value? Are they the same object ?
   You can check it by using the operators ``==`` and ``is``, respectively.

#. After executing these assignment statements:

   .. code:: python

       a = ['a', 5, [], 3.2, [4, 'bc']]
       b = a[-1]

   have ``a[-1]`` and ``b`` the same value? Are they the same object ?
   You can check it by using the operators ``==`` and ``is``, respectively.

#. After executing these assignment statements:

   .. code:: python

       a = ['a', 5, [], 3.2, [4, 'bc']]
       b = [4, 'bc']

   have ``a[-1]`` and ``b`` the same value? Are they the same object ?
   You can check it by using the operators ``==`` and ``is``, respectively.

#. Given the following list:

   .. code:: python

       a = ['a', 5, [], 3.2, [4, 'bc']]

   which is the result of the following print expressions ?. You can check it
   by using the operators ``==`` and ``is``, respectively.

   .. code:: python

       >>> b = a
       >>> print(a, b)
       >>> b[3] = 'x'
       >>> print(a, b) 
       >>> a[0] = 10
       >>> print(a, b) 
       >>> b = a[-1]
       >>> b[0] = 'y'
       >>> print(a, b, a[-1])

#. which is the result of the following print expressions ?. You can check it
   by using the operators ``==`` and ``is``, respectively.

   .. code:: python

       >>> b = [0, 1]
       >>> a = ['a', b, 'c']
       >>> print(a)
       >>> b[0] = 2
       >>> print(b)
       >>> print(a)