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Hello,

I would like to share a channel with some users, but when I do it, they can see the channel in "Channels share with me" but when they open the channel the can not see the data inside. There is a message saying: You don't have permission to view that channel! Do you know why is that? Thank you.

Holger Riedel
Holger Riedel
最後のアクティビティ: 2021 年 2 月 17 日

Hi there, my PI submitted some (3) wrong values to my channel. I didn't find am opportunity to remove them. Can anoyone help or give me a hint? Those 3 wrong values are killing my statistic and let the chart look very wrog due to those peaks Thanx to you

Daniel Dolan
Daniel Dolan
最後のアクティビティ: 2024 年 8 月 7 日

Is anyone else disappointed with uifigures? It seems apparent that these will eventually replace traditional figures, but there is still so much that doesn't quite work. I've tinkered with uifigures since their introduction in release 2016a, but even in 2020a I can't reliably export a uifigure to a graphics file. Sure it works sometimes, but not if a uipanel is present. The exportgraphics command is not as powerful as the print command, leaving some graphic formats (such as *.svg and *.eps) unsupported. How do you generate graphic files of a specific size? You can't even use subplots without overriding the default AutoResizeChildren setting!
Everything with uifigures seems to be slower and less stable than the figure variant. App Designer is much better than GUIDE, but that is not exactly high praise. I would rather generate "apps" programatically across several files instead of dealing with a single-file class definition containing 1000+ lines.
Where is this transition going? MATLAB graphics are moving away from Java in favor of JavaScript, and I'm not sure that we are at all ready for that.
Julia
Julia
最後のアクティビティ: 2021 年 2 月 11 日

ok I want to extract all those rows in a table where one column has strings in which it shall contain the word "change" specifically after the word "terms" . text is : May not be redeemed for cash or combined with any other offer or coupon. Not valid on clearance (merchandise ending in .98). May not be applied to taxes, previous purchases, or the purchase of gift cards. Non-transferable. Terms are subject to change at any time. Product styles are subject to availability. See store associate for details.

Julio Dopazo Alvariñas
Julio Dopazo Alvariñas
最後のアクティビティ: 2022 年 5 月 10 日

Hello, I am interested in creating an IoT academic project, but I have encountered two difficulties: 1- It is necessary that in the ThingSpeak interface you can see a live camera. I have not found documentation or any information on how to do it. Yes, I know that you can import data from other websites (copy XPath), but I have not achieved it with traffic cameras from local websites. 2- I also need to act remotely on actuators, is this possible in ThingSpeak?

I would appreciate an honest answer, since in case of not being able to implement these solutions, I will have to find another platform or method to carry out this. Regards!

Lemuel Aldwin Garcia
Lemuel Aldwin Garcia
最後のアクティビティ: 2021 年 2 月 3 日

Hi,

I would like to export data from my channel. My channel receives data every 15 minutes but I would like to export the data similar to what I can see when I change the chart/field's timescale to 60 minutes.

Thanks!

Volker Bandke
Volker Bandke
最後のアクティビティ: 2021 年 1 月 29 日

Hi everyone,

I have been using Thingspeak for quite some time now for monitoring data for my wife‘s greenhouse. She accesses those data via the public view of the channel. So far, so good.

Now someone has used the „feature“ to add a comment to that view. Nothing serious, but my wife isn‘t happy. Therefore she asked me to remove the comment, and to set things up in such a way that comments can no longer be added.

Thus my two questions: 1. How can I delete the comment? 2. How can I disable comments made by not signed on users?

The channel in question is https://thingspeak.com/channels/971602

With best regards

Volker Bandke

Christopher Stapels
Christopher Stapels
最後のアクティビティ: 2021 年 2 月 7 日

I'm presently working on an Air Quality monitor to be able to check the status of my environment and remote environments on ThingSpeak. I was planning on using the BME680 sensor. Does anyone have any experience with this or other air quality sensors? I'm looking probably for CO2 and the like (Volatile Organics), not so much particle sensors, though a combination may be best.

Frank Mehlhop
Frank Mehlhop
最後のアクティビティ: 2021 年 1 月 20 日

Hi,

I set at the Chart Options Results on 40320, what should be one week. But the graph shows only 36 hours (and some minutes). I also try to set it results on 7 day, but still I get only 36 hours.

Why it is not showing 7 days graph?

Frank

https://thingspeak.com/channels/1222127

Happy New Year, everyone! We hope you enjoyed the Cody contest in 2020, learned new MATLAB skills, and made a friend or two. While the 2020 contest has concluded, the fun and learning never end.

Please take the 1-minute survey to talk about your experience (only 2 required questions). Our goal is to make future contests better and more appealing to you, so your feedback is critical to us.

Thank you in advance and hope to see you again in the 2021 contest.

Christopher Stapels
Christopher Stapels
最後のアクティビティ: 2021 年 1 月 15 日

Right now ThingSpeak supports up to 8 fields of data plus the status and three position fields. If you could have more fields, how many would you want? I have one channel of control settings for a project that I would have used up to 12, but no more than that.

Christopher Stapels
Christopher Stapels
最後のアクティビティ: 2020 年 12 月 21 日

Did you know you can change your user id? We went through a short time where everyone was auto assigned a long user id with 'mwa' and a bunch of numbers that couldn't be changed. You can now make it something more relevant to your actual IoT persona. Click on your user picture or icon on the upper right. Select 'My Profile' and click the Edit button under username. Share your interesting IoT themed names here.

Chen Lin
Chen Lin
最後のアクティビティ: 2020 年 10 月 1 日

We are excited to announce that Cody Contest 2020 starts today! Again, the rule is simple - solve any problem and rate its difficulty. If you have any question, please visit our FAQs page first. Want to know your ranking? Check out the contest leaderboard .

Happy problem-solving! We hope you are a winner.

Chen Lin
Chen Lin
最後のアクティビティ: 2021 年 1 月 23 日

Below are some FAQs for the Cody contest 2020. If you have any additional questions, ask your questions by replying to this post. We will keep updating the FAQs.

Q1: If I rate a problem I solved before the contest, will I still get a raffle ticket?

A: Yes. You can rate any problem you have solved, whether it was before or during the contest period.

Q2: When will I receive the contest badges that I've earned?

A: All badges will be awarded after the contest ends.

Q3: How do I know if I’m the raffle winner?

A: If you are a winner, we will contact you to get your name and mailing address. You can find the list of winners on the Cody contest page .

Q4: When will I receive my T-shirt or hat?

A: You will typically receive your prize within a few weeks. It might take longer for international shipping.

Q5: I'm new to Cody. If I have some questions about using Cody, how can I get help?

A: You can ask your question by replying this post. Other community users might help you and we will also monitor the threads. You might also find answers here .

Q6: What do I do if I have a question about a specific problem?

A: If the problem description is unclear, the test suite is broken, or similar concerns arise, post your question(s) as a comment on the specific problem page. If you are having a hard time solving a problem, you can post a comment to your solution attempt (after submitting it). However, do not ask other people to solve problems for you.

Q7: If I find a bug or notice someone is cheating/spamming during the contest, how can I report it?

A: Use Web Site Feedback . Select "MATLAB Central" from the category list.

Q8: Why can't I rate a problem?

A: To rate a problem, you must solve that problem first and have at least 50 total points.

Rik
Rik
最後のアクティビティ: 2024 年 10 月 7 日

Meta threads have a tendency to grow large. This has happened several times before (the wishlist threads #1 #2 #3 #4 #5, and 'What frustrates you about MATLAB?' #1 and #2).
No wonder that a thread from early 2011 has also kept growing. After just under a decade there are (at time of writing) 119 answers, making the page slow to load and navigate (especially on mobile). So after a friendly nudge; here is a new thread for the things that are missing from Matlab.
Same question: are there things you think should be possible in Matlab, but aren't? What things are possible with software packages similar to Matlab that Matlab would benefit from? (note that you can also submit an enhancement request through support, although I suspect they will be monitoring activity on this thread as well)
What should you post where?
Wishlist threads (#1 #2 #3 #4 #5): bugs and feature requests for Matlab Answers
Frustation threads (#1 #2): frustations about usage and capabilities of Matlab itself
Missing feature threads (#1 #2): features that you whish Matlab would have had
Next Gen threads (#1): features that would break compatibility with previous versions, but would be nice to have
@anyone posting a new thread when the last one gets too large (about 50 answers seems a reasonable limit per thread), please update this list in all last threads. (if you don't have editing privileges, just post a comment asking someone to do the edit)
Rik
Rik
最後のアクティビティ: 2022 年 11 月 4 日

There are multiple ways to create a graphical user interface (GUI) in Matlab. Which method is the best depends on multiple factors: the complexity of the project, to what extent it should be a long-term solution, on what releases your GUI should work, your available time, your skill level, and probably other factors I'm forgetting.
To keep the thread clear I'll attempt to provide a short outline a few ways in this question, and leave the details for the answers. (@anyone with editing privileges: feel free to update the section below if I missed something important and am slow in editing this question)
---------------------------------------------------------------------------------------------------
GUIDE
GUIDE is probably the first tool new users will encounter. It is very useful for quickly putting something together, but it is otherwise fairly limited. It requires maintaining (and distributing) both a .m and a .fig file. Note that the GUIDE environment will be removed in a future release. After GUIDE is removed, existing GUIDE apps will continue to run in Matlab but they will not be editable in GUIDE. If you're starting a new GUI, don't use GUIDE. If you're updating an existing GUIDE GUI, migrate it to AppDesigner. In R2021a the first step for this removal was taken: all templates except the blank template have been removed.
GUILT
Although I haven't had a detailed look myself, it seems a list like this is not complete without at least mentioning the GUI Layout Toolbox, which is available on the file exchange and offers a lot of customization options.
Programmatic GUIs
You can bypass GUIDE and use the normal figures and functions like uicontrol to build GUIs from code. This makes the design less visual, but more flexible for future additions.
App Designer
The official successor to GUIDE, AppDesigner is not based on functions, but works similar to a class. It uses uifigure and mostly uses graphical elements that are incompatible with 'normal' GUIs that are created with a figure (or .fig).
Rik
Rik
最後のアクティビティ: 2024 年 1 月 17 日

This is the 5th installment of the wish-list and bug report thread.
This topic is the follow on to the first Wish-list for MATLAB Answer sections and second MATLAB Answers Wish-list #2 (and bug reports). The third started out as New design of the forum - grey on white and the fourth MATLAB Answers Wish-list #4 (and bug reports) is also growing so large it is slow to load and navigate.
Same idea as the previous ones: one wish (or bug report) per answer, so that people can vote their wishes.
What should you post where?
Wishlist threads (#1 #2 #3 #4 #5 #6): bugs and feature requests for Matlab Answers
Frustation threads (#1 #2): frustations about usage and capabilities of Matlab itself
Missing feature threads (#1 #2): features that you whish Matlab would have had
Next Gen threads (#1): features that would break compatibility with previous versions, but would be nice to have
@anyone posting a new thread when the last one gets too large (about 50 answers seems a reasonable limit per thread), please update this list in all last threads. (if you don't have editing privileges, just post a comment asking someone to do the edit)
Summary:
Dynamically accessing variable names can negatively impact the readability of your code and can cause it to run slower by preventing MATLAB from optimizing it as well as it could if you used alternate techniques. The most common alternative is to use simple and efficient indexing.
Explanation:
Sometimes beginners (and some self-taught professors) think it would be a good idea to dynamically create or access variable names, the variables are often named something like these:
  • matrix1, matrix2, matrix3, matrix4, ...
  • test_20kmh, test_50kmh, test_80kmh, ...
  • nameA, nameB, nameC, nameD,...
Good reasons why dynamic variable names should be avoided:
There are much better alternatives to accessing dynamic variable names:
Note that avoiding eval (and assignin, etc.) is not some esoteric MATLAB restriction, it also applies to many other programming languages as well:
MATLAB Documentation:
If you are not interested in reading the answers below then at least read MATLAB's own documentation on this topic Alternatives to the eval Function, which states "A frequent use of the eval function is to create sets of variables such as A1, A2, ..., An, but this approach does not use the array processing power of MATLAB and is not recommended. The preferred method is to store related data in a single array." Data in a single array can be accessed very efficiently using indexing.
Note that all of these problems and disadvantages also apply to functions load (without an output variable), assignin, evalin, and evalc, and the MATLAB documentation explicitly recommends to "Avoid functions such as eval, evalc, evalin, and feval(fname)".
The official MATLAB blogs explain why eval should be avoided, the better alternatives to eval, and clearly recommend against magically creating variables. Using eval comes out at position number one on this list of Top 10 MATLAB Code Practices That Make Me Cry. Experienced MATLAB users recommend avoiding using eval for trivial code, and have written extensively on this topic.
Matt Tearle
Matt Tearle
最後のアクティビティ: 2023 年 3 月 6 日

Inspired by Chad Greene's " MATLAB jokes or puns " thread, and in celebration of 15 years of the MathWorks Community site, does anyone out there want to share their poetic creativity? Limericks, haiku, sonnets... Go!
And to start off, my (slightly off-topic) submission on Chad's thread:
There was an old math guy called Cleve
who, while teaching, a pipe-dream conceived:
of a language so clean
you can say what you mean!
From our suffering we've all been relieved.