• 12.7
  Generate a sequence of 10 notes with random pitches up to 12 and random durations equal to a random multiple of tenths of a second up to 10 tenths of a second. -> what does "a random multiple of tenths of a second up to 10 tenths of a second" mean? I think that it is rambled. My idea is that it may mean "RandomInteger[10]/10." Thus, I tried and "Correct" Answer was marked. Then, is that the correct English expression???

After coming back from my running of the day for refresh, I read your respose (THANK YOU!), Jingzhou Na. Then, I read my question. Ah-ha! Now, I understand that it was, yes, rambled, but the correct English. However, again, lol... Is there any crystal-clear expression on it? "a random multiple of tenths of a second up to 10 tenths of a second"

THANK YOU again, Jingzhou Na.

Attachments:

thumb up.jpg

Please check the attached file link. I am getting an error message.

I have thought that this daily study group community threads help Wolfram improve their publishing/published study materials. Thus, although it takes time for us to post issues while studying, it is also one thing that we, daily study group attendees, can do for Wolfram as an expression of our appreciation for teaching us and granting us the public access to their great knowledge-based materials and lectures.

Personally, to me, this community threads help me learn that I am not alone to have the issues and can also learn from others by exchanging our experiences, and academic and empirical knowledge. I appreciate Wolfram, in particular, Wolfram U Team, who hosts and administers classes to the public for free. Moreover, I am grateful to all attendees of Wolfram classes to share their knowledge, experiences, and wisdom.

I have been thinking that we appreciate the instructors in general. However, it is easy for us to forget other Wolfram staff who make the classes run well.

THANK YOU, Rory and Eryn for teaching us. I know very well how much time you invest to teach us.

THANK YOU, Cassidy, Roberto, Christine, and Wolfram System Engineers!

What Wolfram does to the public makes a big difference on learners' ends!!! My experience says that Wolfram, in particular, Wolfram Instructors, knows about it very well.

THANK YOU, all other Wolfram attendees!

It's fall now, although it's still sweltering during the daylight due to the global warming (too sweltering.. I am allergic to Sun (lol)). Have an amazing Fall, everyone! See you around...

Sincerely,

Soomi Cheong

Problem solved for ex16.1, correct answer is

EntityValue[Entity["Country", "Switzerland"], EntityProperty["Country", "Flag"]]

It seems for ex16.1, the system really want "everything". I used "Flag" for second argument and the checker marks it as "incorrect" (only for ex16.1) EntityValue[Entity["Country", "Switzerland"], "Flag"]

I believe the exercise is to recognize the first argument is an "Entity" and the second argument is an "EntityProperty". However, I want to mention that for later ex16.x, the checker does not want "everything". For example in ex16.4, the correct answer would be BarChart[EntityValue[EntityClass["Planet", All], "Mass"]]

but if you use the "everything" involved code as in ex16.1 (by changing "Mass" to EntityProperty["Planet", "Mass"]) BarChart[EntityValue[EntityClass["Planet", All], EntityProperty["Planet", "Mass"]]]

the checker will mark it as "incorrect".

Something more about ex16.x involving "Species": There is a high chance that control= will direct you to the correct animal, but "incorrect" InputForm that the checker will mark it as "incorrect". For example, in ex16.13 (the last ex16) control= "koala" gives me the koala picture as the desired output. When I copied the code here, it shows the following

ImageAdd[Entity["TaxonomicSpecies", "PhascolarctosCinereus::2kft4"]["Image"], Entity["Country","Australia"]["Flag"]]

In the notebook, Entity["TaxonomicSpecies", "PhascolarctosCinereus::2kft4"] will be compressed as a orange box with text "koala species specification" because I used control= to made the input.

However, the system is asking for the exact input as Entity["Species", "Species:PhascolarctosCinereus"]

I believe they point to the same species datapage. The first try by control= is marked as incorrect (at least in my interface). Weird.

A similar issue happened for Ex17.6 When I used control= "2500yen", the nature language process returns Quantity[2500., "Yen"]

However, the checker wants Quantity[2500, "Yen"]

I do buy statements from Phil that redoing those exercises to explore the possibilities will enhance my memory and understanding of the Wolfram System. But at some moments, I found ex16.x is just not doable because of the nature language processing, I can do nothing about it.

I solved my problem about those syntax issues using with exercise solutions for 2nd-edition of the book. https://www.wolfram.com/language/elementary-introduction/2nd-ed/answers-to-exercises.html

Ex9.7 and Ex14.7 does not work, the solutions are wrong in the sense that the output is not the same as desired output (does not satisfy the question)

BTW, I encountered some errors simply due to the name of variables. It seems the checker prefers n in Table; i,j in 2-dimensional Table; x,y,z for coordinates; r for radius; theta for angle between (maybe) {0, 360 Degree}; x Degree for x between (maybe) {0,360};

or use the variables named by the question For Manipulate, click the + you can see the name of variable as the name of control bar

Very interesting. The "expected output" in my interface is indeed the true solution to the question (satisfying the question): when n=5, it has 5 colors and so on.

The 2nd edition solution (or the "expected output" in Phil's interface) has 6 colors when n=5, which is a false solution to the question (it does not satisfy the question).

I believe Phil's solution marked as "correct" is the true solution. There is something going wrong with the "expected solution" in Phil's interface but not in mine, which is interesting.

One guess: Phil is working on a previous version of exercise notebook that has not fixed this specific issue. Then the wrong "expected output" matches the wrong solution in 2nd edition of the book.

Attachments:

ex9.7.png

I'm not seeing the error - can you provide some direction?

I believe your answer is one correct way, but the system does not have that in the solution checker. I tried ToUpperCase[StringJoin[Alphabet[]]]

I agree that the checker is often too picky, but I agree with the checker in this case. Capitalize[] capitalizes the first letter of a string; ToUpperCase[] returns a string all in upper case. The results in this example are the same, because the strings are all one letter long. If the example had used samples from WordList[] rather than Alphabet[], then Capitalize[] would have given the incorrect result.

Part of the point of these exercises is to discover new functions. The words for the exercise are usually chosen carefully. If you get stuck on a problem, one possibility is to put words from the exercise instructions into the Wolfram Language & System Documentation Center search box and see what functions pop up. Or look in the guidelines for a major area of the documentation -- like Strings & Text. I liked Rory's comment today where [I believe] he said he spends the majority of his day inside of the documentation.

Hi Rory and Eryn, thank you for your time and support with the study group sessions and answers here.

Could you advise how to overcome the issues with system checks, like this one:

7.13 Use Part and RandomInteger to make a length-100 list in which each element is randomly a Red, Yellow or Green colorswatch.

I tried several options which give the expected outcome, but are deemed incorrect:

• Part[{Red,Yellow,Green},RandomInteger[{1,3},100]]

• Table[Part[{Red,Yellow,Green},RandomInteger[{1,3}]],100]

• {Red,Yellow, Green}[[RandomInteger[{1,3},100]]]

• Part[{RGBColor[1,0,0],RGBColor[0,1,0],RGBColor[1,1,0]},RandomInteger[{1,3},100]]

• Table[Part[{RGBColor[1,0,0],RGBColor[0,1,0],RGBColor[1,1,0]},RandomInteger[{1,3}]],100]

There can be many other ways to get the expected outcome (including replacements inside the list of three colors), and it is tricky to guess what could be the idea behind the "correct" code.

I think it does not make sense to spend hours checking all the possible ways to solve the exercise. Are there some additional hints or solutions to such tricky exercises?

What is the ideology of the following name of a WL function:

FromLetterNumber

I find this name confusing.

Hi Rory, I have no idea how to insert images into the code. I tried copy and paste, and it doesn't work. Apparently, I'm not familiar enough with the very basics of how to copy and paste in Mathematica. Please help.

Hi there! You can access all the lectures and exercises in the course framework! Good luck :) https://www.wolfram.com/wolfram-u/courses/wolfram-language/an-elementary-introduction-to-the-wolfram-language/

What is the intended answer?

The following questions score my answers as INCORRECT:

1. Find the last five digits in 2^1000.

   IntegerDigits[2^1000][[-5;;]]

2. Alphabet[][[2;;26;;2]]

3. Make a line plot of the second-to-last digit in the first 100 powers of 12.

   ListLinePlot[IntegerDigits[12^Range[100]][[All,-2]]]

4. Join lists of the first 20 squares and cubes, and get the 10 smallest elements of the combined list.

   Take[Sort[Join[Range[20]^2,Range[20]^3]],10]

To the best of my knowledge, my answers are materially correct.

Do you have better answers?

I agree. It seems like they're split into roughly 10 chapters each, so you should be able to do quiz 1 by the end of today's class.

@Rory/@Eryn , there's a problem displaying plots when running Wolfram Cloud on an iMac (24-inch M1 2021, macOS 14.6.1, Safari 17.6): tic marks are not scaled correctly. This shows up in the EIWL course framework. For example, Exercise 3.6 looks like this on that hardware/software:

I reported this bug to Wolfram Technical Support (CASE:5170014) back at the end of August. I think I went through all the steps, but I have no sense how long it takes to fix a bug in the cloud environment. They asked me for the $CloudVersion which has the bug; it's now 1.69.0.1 (September 4, 2024).

The problem doesn't happen in the Google Chrome browser on the iMac. I will switch to Chrome. This is a FYI if other students encounter this on an iMac. If you have access to look up the bug report internally, I'd be grateful if you'd see if they're waiting for me to do something.

Exercise 1.4 Compute 5 squared (i.e. 5x5 or 5 raised to the power 2)

->

(My solution)

5x5

5^2

->

the framework says only 5x5 is correct.

->

both of them are correct answers, right? (Hmm... too many wrong answers..)

Attachments:

Exercise-1.4.jpg

thank you for answering. However, I think that there was a misunderstanding because I did not write down.Too many wrong answers have taken too much of my time to post here (lol). I may be better not to in order to save my time.

Let me clarify my question. As the attached clearly shows, the question asks to compute 5 "squared" specifically. Thus, I thought that the answer should be 5^2 as you, Rory, mentioned. However, the problem is that the framework says that it is "IN-correct." Rather, the framework says that "5 x 5" is correct. Yes, outputs of both are the same. Thus, we can use any of them. However, for this particular question, the correct answer should be "5^2," right?

Hmm... too many errors..

BTW: THANK YOU for answering, not ignoring. It means a lot! Arben, Luke, Eun Hyun, and Mike never ignore my question, no matter what it is: I sometimes ask the answer to a poll question. Instructors except Luke mention the answers verbally only. Sometimes it happens so fast. Or, I was following something that the instructor mentioned before.

I remember that the director at Machine Learning department during Arben's ChatGPT daily study group messaged me back with the correct answer and the reason why it was the correct answer (this was exactly what i was looking for) - I always am interested in the rationale (why???!!!).

THANK YOU, Rory! Hopefully, this post can clear my question.I don't understand why the errors occur: again, too many errors.

The problem with the framework is that it will only really take the answer it's expecting to get. The simplest form of this question is Range[5], which is the correct answer. I agree that the question isn't super clear that it's wanting you to actually rewrite the code, rather than simplify the current code.

I believe in you! Keep on double-checking your answers and exploring new ways to get to the solution when your first thought doesn't work.

Rory,

Your solution to this question was also the same as mine, as attached.

->

Then, you solved it wrong?

->

Which one is correct?

Attachments:

Exercise-3.9_Wro...jpg

Yes. The engine tries hard, but it doesn't always get it right. When the examples get more complex, the engine gets far more interesting. I'd love to have a peek under the hood.

You've gotten right answers shown as wrong by the grading-engine. The real challenge is to submit a wrong answer and have the engine judge it as right. Game on, @Soomi

Thanks, Soomi. There are plenty of superior Wolframers (is that a word?); they're just not around this course. Our course instructors are far more qualified. Cassidy is pretty darn qualified too, but she rarely shows her technical chops in courses.

I do hope that the answers (all correct ones) and solutions are available once we finish each exercises.

I understand the sentiment, but I strongly disagree. The goal is to learn, which may not mean getting the right answer. Be tenacious in seeking the expected result, but don't drown in frustration if you can't find it. Sometimes, there's some point to the exercise that may not be obvious on the first (or fifth) try. In those cases, seek to outflank the problem. Look up the official documentation describing the function. You may find the solution there. You may learn something that helps your overall Wolfram knowledge but has nothing to do with the exercise. That's all part of the game. I remember being extremely frustrated when I ran through [most of] the interactive course; I actually abandoned getting the cert.

When you have some time, I recommend checking out Conrad Wolfram's 2010 TED Talk. He's commenting on the fallacious way we teach math in school. It's not about getting the right answer; it's about knowing how to think and learn in a particular system. This course is a bit different: we're learning the [arbitrary] framework of the Wolfram Language; all of its idiosyncrasies. The goal of the exercises is to learn the language: listening/reading and then speaking/writing. Try like heck to get the exercises right, but realize that that's never the goal. And -- please -- have fun in the process. Respect the exercise framework, but have a healthy lack of respect for it, too.

I do hope that the answers (all correct ones) and solutions are available once we finish each exercises.

In the past. exercise answers were available on the online book-editions of the course, and the book exercises are the same as the framework-exercises. I looked for them today; they appear to be gone. If you open up the exercise questions in the book-editions, you get kicked into a Wolfram Cloud place with the same grading engine. I'm pretty good at searching and poking around in archives; I couldn't find them anywhere.

More to the point: I can't think of a single thing I ever learned about the Wolfram Language by looking at those answers. Maybe there was an "Aha!", but I can't remember it.

Getting the right answer is missing the point. I'm not saying to not strive to answer the questions, just don't be obsessed with it. The EIWL framework is a dense course; you can wind up in the weeds if you obsess over getting every #!$$ answer right.

If you look at the Track My Progress link, you'll see a check-box for exercises. What percentage of exercises correct are required to get checked off on that section? I don't know, but I'm pretty sure it's not 100%. "Badges indicate graded exercises for certification." That's not enough information. @Rory: can you tell us what a passing grade is for the graded exercises in a section of the EIWL framework? Thanks.

Exercise 4.6 today is a good example where you should fight to figure it out. If you try

PieChart[{1,1,1,1,1,1,1,1,1,1}]

you'll get a NO PASS. That's correct, but a bad use of the tool. The designers wanted you to do something a bit more clever. Aha! Of course! I'm likely to remember that lesson now. :)

Heya! For this one, your answer isn't quite correct. It's asking for a list going up to 100 and then back down to 1, and you have 100 twice. See if you can use Range to stop the repeated number, and then it should be correct.

You'd need to plot the numbers

1, 2, 3... 100, 99, 98... 3, 2, 1

Your first answer plots the numbers

1, 2, 3... 100, 100, 99, 98... 3, 2, 1

It's a shame the framework doesn't take your RandomInteger[{0,1000}] solution, that seems reasonable to me. But I imagine that the designers want you to use the simplest iteration of the code, which would be RandomInteger[1000], as it's unnecessary to specify that you want between 0 and 1000, as the default minimum is 0.

I think a good answer would probably be the easiest (in class, I was aiming to show a more complex solution)

Plus[10, RandomInteger[{1,10}]

The solution in the video recording is wrong. You have got 4. But 4<10.

If you're going to reference a video, please say which exact video you're discussing and provide a timestamp. It looks like you're talking about the BigMarker video of Monday's first lecture in the course @38:05. Rory was discussing the exercise with RandomInteger[]. He showed:

Plus[RandomInteger[{1,10}],RandomInteger[{1,10}]]

and ran that computation several times. One of those results was 4. I'm certain the grading engine would score his expression above as wrong. I don't think Rory was trying to solve the exercise; he was showing an expression close to what was asked in the exercise. You're right: his language may have been a bit ambiguous.

I will try to give a correct reference:

In the BigMarker video (I do not know any other videos) of Tuesday's second lecture in the course @15:00 Eryn was discussing the exercise with a list of fractions. She did not erase the initial 1, while the question asked to start the list with 1/2.

How would you define a function for tetration (next operation after exponentiation - spell checker really wants titration)? Or something more general to continue the operations to higher values. This easily produces exceptionally large numbers which can quickly exceed a computer's capacity.

Thanks! It is only recently that I learned about such things.

You can also use the scratch notebook within the framework!

Hi Phil! We're glad you like the system, and I completely agree! Big fan of code fragments rather than multiple choice. Yes, we'll be doing the exercises as part of the Daily Study Group this session. Looking forward to seeing you there!