Hi! I'am working through the course "An Elementary Introduction to the Wolfram Language". Whenever I click in the exercises on "CHECK MY SOLUTION" button I get: "Unfortunately, something went wrong with grading". Any ideas how to fix this? Thanks.

I saw your issue using the EIWL exercise engine. I went through the entire course a year ago; I bumped into problems from time to time. One note for @Christine Owens about ticket 5235502. The grading engine for the EIWL exercises consumes significant Wolfram Cloud resources. Güenter may have been bumping into computational quotas in his Wolfram Cloud account. If the engineers attempt to duplicate the problem, they can test that theory by creating a test Wolfram Cloud account at the "free" level of service. They may not see the problem if the attempt to reproduce with a Wolfram Cloud account that has higher computational quotas.

The issue with the grading button seems to be related to my first name containing the German Umlaut "ü." After changing it in the settings from "Günter" to "Guenter," the grading started working properly. It seems that the Umlaut is crashing the grading. Just wanted to bring this to your attention in case others face the same issue.

Not sure why the exercise (Operations on Lists, 5.4) is grading it wrong.

Hello, does anyone have errors when checking the solution for the lesson exercises in the interactive course framework at Wolfram U?

Example: https://www.wolframcloud.com/obj/online-courses/an-elementary-introduction-to-the-wolfram-language/01-starting-out-elementary-arithmetic.html, but I get errors when checking the solution for any lesson: "Unfortunately, something went wrong with grading".

Same error if I download the exercise notebooks from Wolfram U interactive course.

Strangely, error doesn´t appear if I read the EIWL online, which redirects to the Wolfram Cloud for solving the exercises (second edition of EIWL, not third edition):

https://www.wolfram.com/language/elementary-introduction/3rd-ed/01-starting-out-elementary-arithmetic.html;

https://lab.wolframcloud.com/env/a5ef730a-f521-4f35-96f7-f8d428bf0746#sidebar=eiwl/01-starting-out-elementary-arithmetic

here I can check the solutions without error, but this way the tracking of the exercises doesn´t count at Wolfram U course for following my progress...

Thanks for the feedback, Phil!

I am trying to create a Dataset, but have problems if the order of the columns is not the same, or I have cases where some column values are missing. Here is an example of creating one correctly:

Here is what happens if the columns are out of order: (you no longer have the relationships of "rows" of data) I was hoping that they would align correctly. Is there an option/easy way of fixing this. The last case is where a column may be missing (would like if filled in with "Missing" or zero I am used to working in R where these cases are handled with the way that R creates datasets

Thanks for the input. I had looked at sorting and that will work if I have all the values. I am reading in some data that has hundreds of records and many may be missing one, or more, of the fields. What is hard is determining which ones are missing. Since these are Associations I was thinking that I would initialize with a string with all the fields being Missing <|"field"->Missing, "field"->43|> and then add the fields from each record. If there are valid ones at the end of the Association, they should be the ones that are defined [in the example, "field" would be 42]. Will try that out to see if it works. It does work. I put all the fields that I know are in the data at the start of the association initialized to 0, and then follow it with the actual data. Since an association only keeps that last value defined, it works out and also "sorts" the data in the order of the fields that are input. So with a little processing I can get that data I want.

If you looked at the "Traveling Educator" message that I posted here -- the big path on a US map -- you'll see that I had simple text that I was importing into a Dataset. I used SemanticImportString to import that data. There was a bug in my interpretation and my output: my data source had put "Sat" before a date in the table I imported. Look at the output in the dataset: the SemanticImport left that field blank in the dataset it generated. All things equal, I wish that SemanticImportString had generated an error when it saw that unanticipated day-of-week, but it silently put a blank field in. The function didn't complain, and I missed the buggy entry in my database.

You have some blank spots in your data. Whether or not you have blank spots, you need to canonicalize your input. If you're exporting from some database, it should already be canonicalized. If your input isn't coming from a database, you have your choice of tools to massage it. If privacy is not an issue, you could even use ChatGPT to put your data into a form more palatable to input into a database -- any database.

I did one manual massage on my data. Gil had listed Minneapolis St. Paul as a "city" in his list. This is completely understandable by humans what he means -- the twin cities -- but it befuddled the Wolfram Language to put a place-marker for that non-city.

Importing data is definitely a black art. Importing your data will probably wind up being the most difficult part of your task. I suggest downloading the ".txt" file I included with that message, running the code, and scrutinizing the intermediate results. I suspect that some flavor of SemanticImport is what you need.

The question asked during class about Lambda in Python was appreciated! I noticed the following Question/Answer online on the GeeksforGeeks page on Python Lambda Functions.

Q: What is the functionality of lambda?

A: The functionality of lambda functions in Python is to create small, anonymous functions on the fly. They are often used in situations where creating a full-fledged function using def would be overkill or where a function is needed for a short period and doesn’t need a name.

That definitely fits the exact way that Pure Anonymous Functions are used in the Wolfram Language. It's pretty wild that anonymous functions are taught in EIWL before we ever see how to write named procedures. Stephen commented somewhere that kids who see functional programming and never learn procedural styles don't feel that anything is missing. You can definitely see his preferences and thinking oozing out of this text.

Anyone interested in the great thinking around Lambda and functional programming should check out the Steele/Sussman papers on Lambda and Lambda Calculus from the 1975-1980. They make a convincing case for functional programming, including debunking the idea that procedure calls in functional programming are "expensive". They're not formal science papers; they're passionate and witty on their topics. Both enthusiasts and critics of functional programming would learn something from them. Guy Steele went on to write "C: A Reference Manual" in 1984. That book was probably on the bookshelf of every C programmer around. C is about as procedural and non-functional as any language out there. Go figure. Steele went on to be one of the creators of the Java Programming Language at Sun Microsystems.

Sussman is a Computer Science professor at MIT. His big claim to fame is Numerical Evidence that the Orbit of Pluto is Chaotic. This is a big deal: if the planet Pluto's orbit is chaotic, then the motion of all planets, the galaxy, and the universe at large is chaotic. If you tell me that Pluto is only a dwarf planet, I will hit you. Pluto was a planet when these scientists wrote their paper, and the principles are still applicable. Newton's "clockwork universe" is broken, and most of us haven't gotten the memo. If you're curious why Newton and Kepler and Tycho Brahe never figured out that solar system mechanics were chaotic, then read this Wikipedia article. At best, we've been observing for a couple of thousand years; we'd need to watch for a few tens of millions of years to see any divergence. In short, Sussman and Steele pioneered the beginnings of functional programming -- and also did loads of other important stuff.

Stephen has blogged about Lambda Calculus; he clearly thinks in a similar fashion. I don't think Stephen ever collaborated with the "Lambda the Ultimate [xxx]" crowd, but I could be mistaken. Understanding functional programming is tremendously helpful in understanding the Wolfram Language.

Back to the exercises. Lambda on!

The interesting part of this question in my mind is that: RandomInteger[10] is picking an integer from {0,1,2,3,4,5,6,7,8,9,10} which includes 0. So a Note with 0 time will simply disappear. I think a few run of the code you can find some evaluation only having 9 (or less) "real" Notes. In theory, it is possible this piece of code generate nothing.

Agreed Soomi, this question seems a little tough to parse. Glad you found a solution!

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

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. Make a list of the letters at even-numbered positions in the alphabet.

   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.

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.

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!