We will reach out to you with your certificate.

Conrad, I suppose you could dig into Global Preferences, but I personally wouldn't bother if your code is behaving as expected.

What exactly are you trying to do?

Understood! :D

@Rohit Namjoshi Thanks for the references and I'll definitely take a look at the links.

Replace[{3.1,Pi,\[Pi],E,10,21},{x_/;Element[x,Reals]->Framed[x]},{1}]

Unfortunately this also selects the Integers 10 and 21 which is the wrong requirement!

Pi is not a Real, but a Symbol

Replace[{3.1, \[Pi], Pi, \[Pi], 10, 3.14159, E}, { 
  x_ /; (MemberQ[{Real, Symbol}, Head[x]]) -> Framed[x]}, {1}]

creates frames for all but the Integer

I'm really not understanding what upvalues, downvalues, ownvalues, etc. are. Not how they're used, but what they are. I can find the documentation about them in the documentation center, but I never saw that it defines what they are. Can anyone help?

Quiz 3.3 question:

I am stuck on only one output detail with this question and it appeared as a very straightforward piece of code that just doesn't work! Where am I going wrong, what am I missing?

In[84]:= 
Element[\[Pi], #] & /@ {Complexes, Algebraics, Reals, Rationals, 
  Integers, Primes}

Out[84]= {True, False, True, False, False, False}

So Pi belongs to the domain of Reals!

However any of the input variants for Pi cannot be framed as expected with this Replace code:

Try inputting Pi in different ways ...\ [Pi], [FpormaPi], esc pi esc, ...

In[82]:= Replace[{3.1, \[Pi], Pi, \[Pi], 3.14159, E}, {x_Real -> Framed[x]}, {1}]

Out[82]= {
\!\(\*FrameBox[\!\(3.1`\),
StripOnInput->False]\), \[Pi], \[Pi], \[Pi], 
\!\(\*FrameBox[\!\(3.14159`\),
StripOnInput->False]\), E}

How do I frame the Pi symbol?

Syd

@Aristarque Monneron yes, each solution to the programming exercises in quiz 3 gets automatically graded and submitted when you click "Check Solution". We see your submissions for quiz 1 and 2 but not for quiz 3. Could you please email wolfram-u@wolfram.com and follow up with your notebook?

Confirmation of quiz completion?

Hi Abrita: Many thanks to you and to the team for the presentations. I have submitted the quizzes (1,2,3(part)) and seen the confirmed "OK"s for correct answers: but no overall "congratulations, we'll get back to you" message. Is such a thing expected, to reassure me before the deadline? Thanks Peter (peter.ransome@ieee.org)

Hi Mitchell

I think Abrita's comment is quite clear on where ToString is not needed

Firstly {"a3bykmn","oka2bcka","bdkba1","4ckxyz"} is already a list of Strings so you do not need ToString for the input.

and where it is needed

You would need to use ToString to convert the digit back to String once you have isolated it and decremented it by 1

The code you posted earlier is close

StringReplace[{"a3bykmn","oka2bcka","bdkba1","4ckxyz"},p:DigitCharacter :>ToExpression[p-1]]

Just need to fix the ToExpression[p-1]]. p is a String, it needs to be converted to an Integer so 1 can be subtracted from it, the result needs to be converted to a String so StringReplace can do the replacement.

Hi;

Based on the definition and hints given by the problem, I think that everything is included in my solution, however I am not getting the desired output - see below. I am sure that it is something that I am doing incorrectly, but based on my knowledge at this point in time, I do not have a clue.

StringReplace[ToString[{"a3bykmn","oka2bcka","bdkba1","4ckxyz"}],p_DigitCharacter :>ToExpression[p-1]]

Hi Abrita;

I incorporated the changes that you suggested (see below) and this time, I think the program actually blew up because I never received an answer back as to whether the program actually completed. In any event, I am not getting an option to try again.

However, the comments as to when to use an _ verses a : were very helpful.

StringReplace[{"a3bykmn","oka2bcka","bdkba1","4ckxyz"},p:DigitCharacter :>ToExpression[p-1]]

Hi Rohit;

The problem stated as hints that ToString[] and ToExpression[] would be needed in the solution of StringReplace[]. Abrita told me in a previous reply that I really didn't need to use ToString since the data was already in string format, so I remove it from my expression.

I need to read the digit characters from the data strings, for example pull the 3 from the first string a3bykmn, then subtract 1 from the value, write it back out as a 2, and then grab the next digit character from the next string oka2bcka which is a 2 subtract 1 giving 1 and so on.

Even after attending every lecture, I don't know how to do that.

Thanks,

Mitch Sandlin

Hi Abrita; Referring to 3.3 we are instructed to use Replace[] along with a set of rules to process even, odd and non integers. My solution only wants to process the first element of the string - see below.

Clear[x,y,z]
Replace[#,{x_/;EvenQ[x]->x*2,y_/;OddQ[y]->y*3,z_/;!IntegerQ[z]->Framed[z]}]&  [94,87,[Pi],49,46,"42",28,47,68,57,4,44,100,4.2,{23,1},57]

For example, if you run the function, it will return 188 (294). If you replace the first element of 94 with 87 and run the function, it will return 261 (387). If you replace the first element of 94 with Pi and run the function, it will return Pi with a box around it. Therefore, the logic seems to be working correctly, I just can't get the evaluation to move through the list, and I think I have tried everything that I can find in the documentation as well as the lecture notes. Do you have any suggestions.

Thanks, Mitch Sandlin

@Conrad Taylor Referring to the third template for creating a SparseArray on http://reference.wolfram.com/language/ref/SparseArray.html SparseArray[data,{d1,d2, ...}], we would like you to create your own 'data' with a rule (of the form pattern -> value). The example showing the construction of a tridiagonal matrix using patterns for indices on the documentation page linked above, may be a good starting point to solve this problem.

Hi Conrad;

I followed the example that you sent me a link to for SparceArray and again produced exactly the same output as the problem displayed, but still was not accepted as the correct answer. I do not know that to do at this point. Any suggestions.

Mitch Sandlin

Hi Doug;

Following your advice, I deleted my data from my SparseArray[] and moved it into a field named dta1= {{1,5}-> 1, etc.}}. Then loaded the data into the functions:

MatrixPlot[SparseArray[dta1,{20,20}]]

The new configuration gave me the exact same data as expected, as I have gotten for the last 5 days, with no error messages. However again, the grader didn't like it, gave me an X and told me to try again.

Thanks,

Mitch Sandlin

Hi, I was able to refactor Quiz 3 Problem 3.1 into a solution that appears to have been accepted by the backend. Also, I was definitely in the weeds for this problem. Anyway, could someone confirm that I have submitted all 3 quizzes for the study group?

ReplaceAll[x will only match a literal x e.g.

ReplaceAll[x :> y][{a, x, x^2}]
(* {a, y, y^2} *)

For this quiz question use Replace with a level specification (which is what the quiz asks for). Rather than nested If, consider using Which.

Hi Rohit;

Thanks for the reply directing me to use Which[] as opposed to using a nested If[]. However, I still do not understand why the nested If[] failed. I actually believe the Which[] is a much cleaner solution but unfortunately it doesn't seem to work either - see below. I actually tried both formats using RelpaceAll[] and // with no success.

As an aside, I even tried using x--EvenQ[x], x*2, with no success.

ReplaceAll[x,x:>Which[EvenQ[x],x*2,OddQ[x],x*3,!IntegerQ[x],Framed[x]]]{94,87,\[Pi]}

{94,87,\[Pi]}//.x_:>Which[EvenQ[x],x*2,OddQ[x],x*3,!IntegerQ[x],Framed[x]]

You are welcome, Abrita. I will post it as a separate post as well.

[@Dave Middleton][at0] this is fantastic, especially in helping new users to find their way around the Entity framework. Can I request you to submit your notebook to the [Notebook Archive][1] and also create an independent post on community? You can add the groups like "Wolfram Language" or "Education" as well as "Data Science" when you post.

You're welcome Lori.

Even though the exercise to create a short tutorial made me wiser, I will still refer to it whenever I need entities :)

@Rohit Namjoshi I was able to refactor into a better solution. Thanks for your assistance.

Yes Quiz 3 has only 5 questions.

Hi Doug,

Names ["Developer`*"] // 
  Partition[#, UpTo@3] & // 
  Grid[#, Alignment -> Left, Frame -> All] &

Conrad

If you press Get Results After a few seconds you should see your score below the button

Sometimes no score is given (I think the server may be too busy , or my connection is too slow ) and I just repeat the procedure until I get a score

Hi;

Working on problem 3.4, I have tried a number of techniques with absolutely no success. I can't seem to get the number recognized as a number since the If statement doesn't want to subtract 1 and I seem to be fighting constant errors. In the code below, I am outputting the whole If statement which highlights the problem. Any suggestions as to what I may be doing incorrectly?

StringReplace[ToString[a3bykmn],p_ :> If[DigitCharacter[p],p-1,p]]


If[DigitCharacter[a],a-1,a]~~If[DigitCharacter[3],3-1,3]~~If[DigitCharacter[b],b-1,b]~~If[DigitCharacter[y],y-1,y]~~If[DigitCharacter[k],k-1,k]~~If[DigitCharacter[m],m-1,m]~~If[DigitCharacter[n],n-1,n] 

When I move the RuleDelayed to the end of the statement, all I get is an error.

StringReplace[ToString[a3bykmn],{p_ , If[DigitCharacter[p],p-1,p]} :>P]

Hi;

What am I doing wrong here on the 1st problem - see below? I have included everything the problem indicates, but I am getting a syntax error regarding the position of my rule.

MatrixPlot[ SparseArray[data,{n,n} /;n>0]]

Thanks,

Mitch Sandlin