Error reported in course pythonds on page ObjectOrientedProgramminginPythonDefiningClasses by user [email protected] [email protected]
I understand the implementation of the gate classes.
However, I am struggling to see how 'source' is used in the 'setNextPin' function.
I have had a look through Codelens.
I can see how the ToGate calls the output (self.pinA/B.getfrom().getOuput()) using the Connector but I don't see how the setNextPin function calls the FromGate of the c1 as the source
Please help if you can
Frank

Error reported in course pythonds on page http://127.0.0.1:8000/runestone/default/reportabug
This issue is to test using Github tokens instead of standard user credentials in the Github API enabled bug reporting system. Please ignore this error.

Link

Listing 1 requires explicit import of operator module to function correctly. Should this be included in the listing?

opers = {'+':operator.add, '-':operator.sub, '*':operator.mul, '/':operator.truediv}

Error reported in course pythonds on page ObjectOrientedProgramminginPythonDefiningClasses
My Username: rb7
My Email: [email protected]

https://docs.python.org/3/library/operator.html
if I define division as truediv, it works in python 3.5.2
def truediv(self,other):
newnum = self.num * other.den
newden = self.den * other.num

     common = gcd(newnum,newden)

     return Fraction(newnum//common,newden//common)

However, in the course activecode, only div method definition works.

Are we dealing with python 3 or python 2 or not? I am slightly confused.

Error reported in course pythonds on page InfixPrefixandPostfixExpressions by user i3rend4nv05 [email protected]
Third self check problem is cut off in chrome, showing only "5 * 3 ** (4 - " instead of "5 * 3 ** (4 - 2)".
Correct answer requires use of "^" operator despite the fact that the problem uses the "**" operator.

Found on page: Recursion/Dynamic Programming

Paragraph with class _19002997 reads Although the algorithm in AcitveCode 3 is correct, it looks and feels like a bit of a hack. when it should read Although the algorithm in AcitveCode 1 is correct, it looks and feels like a bit of a hack.

Is there an epub available? Or are there instructions how to produce an epub?

There are two files that use fillintheblank. Since the non-backward compatible changes were made to the new directive we need to update the text in the book.

• BasicDS/ConvertingDecimalNumberstoBinaryNumbers.rst:
• BasicDS/InfixPrefixandPostfixExpressions.rst:

Error reported in course pythonds on page InfixPrefixandPostfixExpressions by user mmarchese1 [email protected]
The third self-check problem is to convert "5 * 3 ** (4 - 2)" to postfix. The correct answer is "5 3 4 2 - ** *", but your webpage is looking for "5 3 4 2 - ^ *".

Hi,

In the following text (from section 5.5.2, Collision Resolution, just before figure 11) I think the 1, 3, 5, 7... sequence should be 1, 4, 9, 16, 25, 36.
It would also be good to clarify with an equation, for example:
The ith skip will be i^2, meaning the ith probe be (h+i^2)%sizeoftable

A variation of the linear probing idea is called quadratic probing. Instead of using a constant “skip” value, we use a rehash function that increments the hash value by 1, 3, 5, 7, 9, and so on. This means that if the first hash value is h, the successive values are h+1, h+4, h+9, h+16, and so on.

Cheers,
Paul McKeown.
University of Canterbury, NZ.

Found on page SortSearch/TheBinarySearch

Which group of numbers correctly shows the sequence of comoparisons used to search for the key 16? should read Which group of numbers correctly shows the sequence of comparisons used to search for the key 16?

Error reported in course pythonds on page InfixPrefixandPostfixExpressions by user leefoster1992 [email protected]
Hi there, just noticed the last problem has ** to indicate the exponent, but the answer only works if ** is replaced by ^

Error reported in course pythonds on page index by user thecodingconductor [email protected]
The chapter 3.7 in the pythonds book throws a 404. Love the book!

Error reported in course pythonds on page TowerofHanoi by user belozi [email protected]
In the explanation to the Tower of Hanoi problem, the author has the pegs labelled with variable names, but discusses the problem in terms of peg numbers. This makes understanding the material confusing.

The anagram solution 1 return true when run with print(anagramSolution1('abcd','addcb')).
I think the problem is where after running the stillOK statement that return False, upon exiting if statement, it is assigned stillOK = True, which cause it to enter the while loop even when the length does not match.

I have added an else statement after the stillOK = False and it returns the expected result.

def anagramSolution1(s1,s2):
alist = list(s2)
pos1 = 0
if len(s1) != len(s2):
stillOK = False

else:
    stillOK = True

while pos1 < len(s1) and stillOK:
    pos2 = 0
    found = False
    while pos2 < len(alist) and not found:
        if s1[pos1] == alist[pos2]:
            found = True
        else:
            pos2 = pos2 + 1

    if found:
        alist[pos2] = None
    else:
        stillOK = False

    pos1 = pos1 + 1

return stillOK

Error reported in course pythonds on page http://127.0.0.1:8000/runestone/default/reportabug
This report is to test the new Github API bug report system for the Runestone textbooks. Please ignore this issue.

Error reported in course pythonds on page VocabularyandDefinitions by user Viktor.Palchyk [email protected]
In Definition One it is written that:
"If each node in the tree has a maximum of two children, we say that the tree is a binary tree."
Then it is stated: "Figure 3 illustrates a tree that fits definition one. The arrowheads on the edges indicate the direction of the connection."
Actually on Figure 3 I can see 3 children for node1.
Isn't it a mistake?

pre-order traversal code currently looks like this in the book . In-order and post-order traversals handle the case where the tree might be empty , but not pre-order. Would be nice to add a check here.

def preorder(self): print(self.key) if self.leftChild: self.leftChild.preorder() if self.rightChild: self.rightChild.preorder()

Listing 3 on this page : http://interactivepython.org/runestone/static/pythonds/Trees/TreeTraversals.html

In a_proper_python_class.rst both activecodes have the same ID.

Error reported in course pythonds on page DiscussionQuestions by user i3rend4nv05 [email protected]
Questions 3 and 5 are identical in section 2.10 Discussion Questions

Error reported in course pythonds on page DijkstrasAlgorithm by user CMZ [email protected]
I copied the algorithm code and and added in some vertexes and edges like in an earlier chapter but it is always giving the response that the distance is 9223372036854775807:
from pythonds.graphs import PriorityQueue, Graph, Vertex
def dijkstra(aGraph,start):
start = Vertex(start)
pq = PriorityQueue()
start.setDistance(0)
pq.buildHeap([(v.getDistance(),v) for v in aGraph])
while not pq.isEmpty():
currentVert = pq.delMin()
for nextVert in currentVert.getConnections():
print("2")
newDist = currentVert.getDistance()
+ currentVert.getWeight(nextVert)
if newDist < nextVert.getDistance():
nextVert.setDistance( newDist )
nextVert.setPred(currentVert)
pq.decreaseKey(nextVert,newDist)

g = Graph()
for i in range(6):
g.addVertex(i)

g.addEdge(0,1,1)
g.addEdge(0,5,2)
g.addEdge(1,2,4)
g.addEdge(2,3,9)
g.addEdge(3,4,7)
g.addEdge(3,5,3)
g.addEdge(4,0,1)
g.addEdge(5,4,8)
g.addEdge(5,2,1)
start = Vertex(1)
dijkstra(g,start)
print (Vertex(2).getDistance())

Remove extra characters from first paragraph. trade-ÁÁ off should be trade-off

QuickSort

Error reported in course pythonds on page http://interactivepython.org/runestone/static/pythonds/SortSearch/Hashing.html#hash-functions by user anonymous [email protected]
Hi, in 5.5.1 Hash Functions of Problem Solving with Algorithms and Data Structures using Python, last line of the 4th paragraph. I think you meant to say ..."34"+56+55+64+"10"=219... The 43 and the 01 are not reversed.

From @delimitry on July 15, 2015 12:58

Superfluous ")" parenthesis in del operatrion for Sorted List O(n))

http://interactivepython.org/LpOMZ/courselib/static/pythonds/Trees/SummaryofMapADTImplementations.html

Copied from original issue: RunestoneInteractive/RunestoneServer#606

Error reported in course pythonds on page BinaryHeapImplementation by user TheEpsylon
"To finish our discussion of binary heaps, we will look at a method to build an entire heap from a list of keys. The first method you might think of may be like the following. Given a list of keys, you could easily build a heap by inserting each key one at a time. Since you are starting with a list of one item, the list is sorted and you could use binary search to find the right position to insert the next key at a cost of approximately O(logn)O(log⁡n) operations. However, remember that inserting an item in the middle of the list may require O(n)O(n) operations to shift the rest of the list over to make room for the new key. Therefore, to insert nn keys into the heap would require a total of O(nlogn)O(nlog⁡n) operations. "

What you're describing is insertion sort! It has a cost of O(n^2). This is not the naive way: the naive way is to repeatedly insert for a total cost of O(n log n) (is that what you were trying to explain?).

Error reported in course pythonds on page GettingStarted by user navidpaya [email protected]
The progress indicators using the green color ticks and yellow bullets are wrong. It shows lessons I have never opened as completed with the green tick and then if I go to them, it shows me the mark as completed button.

Error reported in course pythonds on page index
My Username: andy1998410
My Email: [email protected]
On the page (http://interactivepython.org/runestone/static/pythonds/Trees/AVLTreePerformance.html#fig-worstavl) AVL Tree Performance, the equation Nh = Fh+2 - 1 for h >= 1 is given, which should be Nh = Fh+3 - 1 (for example, for h=2, N2= 4, f4 = 3, f5 = 5). I understand that counting can be different, depending on initial conditions, but with the numbers provided in the text, the equation does not hold and may be misleading.

Thanks for the great book and interface.

Best,

Andy

Error reported in course pythonds on page ControlStructures by user Shashank [email protected]
At the last section of Control Structures which is 'Self check' its written "For an extra challence, see if you can figure out how to remove the duplicates"
Here challence mist be equal to challenge.

I believe the wording of the answer to question intro-8-2 in Chapter 1.8 Runtime Errors of How to Think Like a Computer Scientist could be improved.

The question is Who or what typically finds runtime errors?

The expected answer is The compiler/interpreter.

I would like to see the answer changed to be The interpreter.
It is my view that a compiler finds compile-time errors, not run time errors.

Error reported in course pythonds on page https://runestone.academy/runestone/books/published/pythonds/ProperClasses/make_your_class_comparable.html by user agneshe [email protected]
2.2. Making your class comparable is empty.

The BinaryTree class does not work if you are creating one with more than two layers, as the children are assigned to the wrong instance variables in the insert methods.

Method insertLeft | Line 30:
t.left = self.leftChild
should be
t.leftChild = self.leftChild

Method insertRight | Line 41:
t.right = self.rightChild
should be
t.rightChild = self.rightChild

Error reported in course pythonds on page Exercises by user aw9677 [email protected]
Line 15 of the solution to activity 12.7 is missing the conversion to list, currently it reads:
keys = letter_count.keys()
And it should read:
keys = list(letter_count.keys())

Error reported in course pythonds on page GettingStartedwithData by user UPS [email protected]
In the following code when we print(A) after changing the element in myList - A shows the new value whereas if I run the same code on my local or an online REPL, it prints the same value as before for A

myList = [1,2,3,4]
A = [myList]*3
print(A)
myList[2]=45
print(A)

Output in runestone: [[1, 2, 3, 4], [1, 2, 3, 4], [1, 2, 3, 4]]
[[1, 2, 45, 4], [1, 2, 45, 4], [1, 2, 45, 4]]

Output in local: [1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4]
[1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4]

Error reported in course pythonds on page TheMergeSort by user flavianshem [email protected]
The implementation of the merge sort makes it an unstable sort algorithm. During merging, if two elements from both halves are equal, the left element should be added to the list first before the right element.

I guess the original authors might have to take a look to decide this . But In the implementation of Graphs, can we just use "weight" instead of "cost". I suppose most readers would ofcourse understand that its conceptually the same , but I guess it would be more homogenous if the book used 'weight'

    def addEdge(self,f,t,cost=0):
        if f not in self.vertList:
            nv = self.addVertex(f)
        if t not in self.vertList:
            nv = self.addVertex(t)
        self.vertList[f].addNeighbor(self.vertList[t], cost)

    ```

http://interactivepython.org/runestone/static/pythonds/Graphs/Implementation.html

Error reported in course pythonds on page ImplementinganUnorderedListLinkedLists by user anonymous [email protected]
The Complete UnorderedList Class (unorderedlistcomplete)
This active code has error in the remove function.
When you supply to a value to remove function that is not in the list, it gives a syntax error.
The condition where current becomes equal to None is not handled. Maybe there should be message like "Not found"

Error reported in course pythonds on page TheBinarySearch by user Amresh [email protected]
The answers given are incorrect.
Q-13 - (A) 11, 5, 6, 8
Q-14 - 11, 15, 17

Fix .rst file to correctly link to online book

In this page:
https://runestone.academy/runestone/books/published/pythonds/SortSearch/TheQuickSort.html
in question 4, if you select an incorect answer, it looks like this:

There shouldn't be double backticks by some of the answers. I was using Firefox.

Missing space before :ref: in file AnAnagramDetectionExample.rst

replacement.:ref:ActiveCode 1 <lst_anagramSolution>

Error reported in course FIT5211 on page Lists by user lwoo0004 [email protected]
Incorrect info on page ... pop(i) is O(k) not O(n).
e.g. popping from an indexed location from the end of a list

See python docs:
https://wiki.python.org/moin/TimeComplexity
Pop intermediate O(k)

And revised code:

popzero = timeit.Timer("x.pop(0)", "from main import x")
popend = timeit.Timer("x.pop()", "from main import x")
popend_minus = timeit.Timer("x.pop(-2)", "from main import x") . # ADDED

print("pop(0) pop() pop(-2)")
for i in range(1000000,100000001,1000000):
x = list(range(i))
pt = popend.timeit(number=1000)
x = list(range(i))
pz = popzero.timeit(number=1000)
x = list(range(i))
pe = popend_minus.timeit(number=1000)
print("%15.5f, %15.5f, %15.5f" %(pz,pt,pe))
pop(0) pop() pop(-2)
0.40309, 0.00010, 0.00015
1.20204, 0.00009, 0.00017
1.93542, 0.00009, 0.00014
2.73203, 0.00009, 0.00014
3.45721, 0.00010, 0.00015
4.21476, 0.00011, 0.00015
5.14111, 0.00010, 0.00017

Tree Traversals

Missing the word "parentheses" in last sentence.

The section titled "What Is Computer Science?" begins with the sentence:

Computer science is often difficult to define.

The word "often" detracts from the very important idea of the sentence, which would be strengthened by simply omitting it.

Cannot configure a Database URL!
Skipping all DB operations because environment variables not set up

Got the above error while trying to build. How do I get the URL to configure in the environment variable

From @bnmnetp on August 14, 2016 9:16

Error reported in course Problem Solving with Algorithms and Data Structures on page http://interactivepython.org/runestone/static/pythonds/AlgorithmAnalysis/AnAnagramDetectionExample.html
My Username: tingRay
My Email: [email protected]
Description: In solution 1 of Anagram detection problem for strings, the output of 'anagramSolution1('abcd','dcgba')' will be True.Obviously,it is incorrect.

Copied from original issue: RunestoneInteractive/RunestoneComponents#224

Error reported in course pythonds on page InfixPrefixandPostfixExpressions by user vemkiran [email protected]
In the last self check question that states "Modify the infixToPostfix function so that it can convert the following expression", the expression provides is "5 * 3 ** (4 - 2) ".

So the answer generated by the program is "5 3 4 2 - ** *"

But when I enter that answer and submit, it says incorrect. But when I replace ** with ^, it accepts it as a correct solution.

The idea is that in the case where the the first item in the list does not belong toward the middle of the list, the median of three will choose a better “middle” value.

http://interactivepython.org/courselib/static/pythonds/SortSearch/TheQuickSort.html

What Course are you in
https://runestone.academy/runestone/books/published/pythonds/Graphs/DiscussionQuestions.html

Describe the bug
The numbering of the questions is wrong (there are 2 number 1s). Also, for the current question 2, is there a goal to the breadth first search? Is it too find the shortest path, ignoring the weights?