6. Exercise solutions¶

Exericse 1¶

In [1]:

class Accumulator():

    def __init__(self, start=0):
        self._sum = start

    def __call__(self, x):
        self._sum += x
        print(f"I've now added {x} to my sum")

    @property
    def current_sum(self):
        return self._sum

In [2]:

# initializing two instances with different starting values
adder_A = Accumulator(start=2)
adder_B = Accumulator(start=3)

In [3]:

adder_A(3)

I've now added 3 to my sum

In [4]:

adder_B(4)

I've now added 4 to my sum

In [5]:

adder_A(5)

I've now added 5 to my sum

In [6]:

adder_B(6)

I've now added 6 to my sum

In [7]:

adder_A.current_sum

Out[7]:

In [8]:

adder_B.current_sum

Out[8]:

Exericse 2¶

In [9]:

class Count_to_10():
    
    def __init__(self, start=0, step=1):
        self.num = start
        self.step = step
        
    def __iter__(self):
        return self
    
    def __next__(self):
        self.num += self.step
        if self.num > 10: 
            print('I can only count to 10! :(')
            raise(StopIteration)
        return self.num
    
    def set_step(self, step):
        self.step = step

In [10]:

counter = Count_to_10(start=0, step=1)

In [11]:

next(counter)

Out[11]:

In [12]:

next(counter)

Out[12]:

In [13]:

counter.set_step(2)

In [14]:

for count in counter:
    print(count)

4
6
8
10
I can only count to 10! :(

End of exercises¶

The cell below is for setting the style of this document. It's not part of the exercises.

In [15]:

# Apply css theme to notebook
from IPython.display import HTML
HTML('<style>{}</style>'.format(open('../css/cowi.css').read()))

Out[15]: