Exercise, Chapter 02: OOP, In [14]:

def __contains__(self, item):
    return True if (item - self._start) % 5 == 0 else False

I think the number 5 should be replaced by self._step 😄

Range # built in range

r = Range(-1, -7, -2) | r = range(-1, -7, -2)
out: [-1, -3, -5, -7] | out: list(r) [-1, -3, -5]

r = Range(-1, -7, -1) | r = range(-1, -7, -1)
out: list(r) -> [-1, -2, -3, -4, -5, -6, -7, -8] | out: list(r) -> [-1, -2, -3, -4, -5, -6]

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Hey @jihoonerd i noticed that chapter 6 had some missing solutions R 6.8 onwards. Are the solutions of those questions located elsewhere in the repository or do they not exist at all?

(Some of those questions are follow ups on previous questions but some are new as well)

I see the solutions are present for chapters 1 through 8. Will solutions for remaining chapters be available in future?

In the source code author provided in wiley, I find author did not write this class. Authors used from ..exceptions import Empty but it did not work on my PC(Python 3.6, Win10). Also, there is no fold called exceptions in the source code on wiley.com.

If I did not get you wrong, the source code provided on wiley.com is incompelete and we must write our own class Empty(Exception): to make the code usable? This is the reason you write class Empty(Exception): ?

Thanks a lot for providing notebooks and revised pure python code!

I think there are something wrong in the solution of Chap3, R-3.27.

Firstly, the time complexity of example5 should be O(n^3).

Then, there are some problems when we collect data from example5 for plot. I think we can do it by changing the code a little bit. Like this:

def example5(A, B):
    n = len(A)
    count = 0
    num_calc = 0
    for i in range(n):
        total = 0
        for j in range(n):
            for k in range(1+j):
                total += A[k]
                num_calc += 1
        if B[i] == total:
            count+=1
    return count, num_calc

def get_time_complexity_2(n=100):
    op_nums = []
    for i in range(1, n):
        A = np.random.randint(0, 100, size=(i, ))
        B = np.random.randint(0, 100, size=(i, ))
        _, num_calc = example5(A, B)
        op_nums.append(num_calc)
    plt.plot(op_nums)
    plt.plot(range(n), [i**2 for i in range(n)])
    plt.plot(range(n), [i**3 for i in range(n)])
    plt.legend(['example5', '$n^2$', '$n^3$'])
    plt.title('example5')
    plt.show()

And the plot should like this:

Doing a pip search yielded no results for the actionlib package. Can the name of the package be updated in the requirements.txt file

Pip install seems to be failing with this output on python 3.8/3.9

ERROR: Could not find a version that satisfies the requirement actionlib==1.13.2 (from versions: none)
ERROR: No matching distribution found for actionlib==1.13.2