Tag: Downloadable Source Files

Warning Messages in Jupyter Notebook Example Code

You’re working with the downloadable source code from a book like  Algorithms for Dummies, 2nd Edition, Beginning Programming with Python For Dummies, 3rd Edition, Machine Learning for Dummies, 2nd Edition, Python for Data Science for Dummies, or Machine Learning Security Principles and see a warning message like this:

C:\Users\John\anaconda3\lib\site-packages\sklearn\feature_selection\_sequential.py:206: FutureWarning: Leaving `n_features_to_select` to None is deprecated in 1.0 and will become 'auto' in 1.3. To keep the same behaviour as with None (i.e. select half of the features) and avoid this warning, you should manually set `n_features_to_select='auto'` and set tol=None when creating an instance.
  warnings.warn(

Well, that’s pretty confusing looking and if you’re just learning to work with Python may give you the idea that you’ve done something seriously wrong. There are a couple things to note here. First, this is a warning message. In fact, it’s a FutureWarning message, which means the change mentioned in the warning hasn’t actually taken effect yet.

Second, if you’re using the version of Jupyter Notebook and Python mentioned in the book, it’s unlikely that the effects described in the message will become a problem anytime soon, so you can usually ignore them. (This is one reason that I always ask which version of Jupyter Notebook and Python you’re using because a newer version can definitely cause error messages to appear.) Of course, if this warning ever does turn into an error, Luca and I definitely want to hear about it at [email protected].

Third, the message does state a potential fix for the problem. If the fix is simple enough, you can always try to make the required change to see if it works. However, this is a do it at your own risk sort of modification. The point is that the warning isn’t keeping you from using the downloadable source today, so ignoring it is probably the best action to take.

If you really don’t want to see these warnings, you can always add two lines of code the to first cell of the downloadable source. The warning isn’t actually going away, you just won’t see it:

import warnings
warnings.simplefilter(action='ignore', category=FutureWarning)

So, what causes these warning messages in the first place? Is the book’s source code faulty? There is nothing wrong with the book’s source code. What you’re seeing is the result of a library upgrade. Python uses a huge number of libraries and a change in any one of them can create a warning message of the sort you’ve seen. Luca and I work hard to ensure that the source code you get with the book is functional (and warning free) on all of the supported platforms at the time of writing, but it would be impossible for us to constantly update the book’s code to keep up with these library changes.

Pausing the C++ Example Output

This is an update of a post that originally appeared on December 23, 2013.

A number of readers have written to ask about running the example code in C++ All-In-One for Dummies, 4th Edition. The book shows that the examples pause so you can see the output, yet a few people experience problems getting the example to pause as shown in the book. Let’s take the first book example. When you run the example, you should see a command window similar to the one shown here open.

The paused output of a Code::Blocks example.
The paused output of a Code::Blocks example.

This is how the command window looks in Windows, but if you use some other operating system, you should see something similar. Notice that the output is paused. Pressing any key will cause the window to disappear and the example to end. The purpose of pausing the output is so that you can see the result.

There are two common reasons that people aren’t seeing the output pause. The most common reason is that the example is run in debug mode. Make sure you click Run or choose Build | Run to execute the example. If you click Debug/Continue or choose Debug | Start/Continue instead, the example will execute without pausing and you won’t see the output. Of course, you can always set a breakpoint to get the example to pause, but most people simply want to see the example output which means running the example, rather than debugging the example.

A less common cause is that the project environment is configured incorrectly. Normally the Code::Blocks environment automatically pauses when you run the example. However, it’s possible to set Code::Blocks not to pause. Some readers inadvertently change this setting while exploring the environment. In order to check this setting, choose Project | Properties to display the Project Targets/Options dialog box. Select the Build Targets tab and you see the dialog box shown here.

The Build Targets tab of the Project Properties dialog box contains a Pause When Execution Ends setting.
Changing the default Code::Blocks settings can cause the IDE not to pause the output.

Notice the Pause When Execution Ends option. If this option is cleared, the example won’t pause when you run it. Make sure this option is checked and click OK. The projects that come with the downloadable code all have this setting set up correctly.

Of course, there could always be other reasons why the examples aren’t pausing. Please let me know if you have any problems setting the example output. It’s essential that you be able to see the example output as you follow along in the book to understand how C++ works. Send your queries about this (or any other book-specific) topic to [email protected]. I always want to ensure you have the best possible experience when using my books.

Machine Learning for Dummies, 2nd Edition, MovieLens Dataset

Updated March 15, 2023 to clarify the usage instructions.

The movies.dat file found in the Trudging through the MovieLens dataset section of Chapter 19 of Machine Learning for Dummies, 2nd Edition has been updated on the source site, so it no longer works with the downloadable source. Luca and I want to be sure you have a great learning experience. Fortunately, we do have a copy of the version of movies.dat found in the book. You can download the entire MovieLens dataset here:

MovieLens DatasetDownload

To obtain your copy of the MoveLens dataset for your local Python setup, please follow these steps:

  1. Click the link or the Download button. The ml-1m.zip file will appear on your hard drive.
  2. Remove the files from the archive. You should see four files in a folder named ml-1m: movies.dat, ratings.dat, README, and users.dat.
  3. Place the files in the downloadable source directory for this book on your system.

Note that you may not be able to use automatic downloads with my site, which is a security measure on my part. In addition, it ensures that you get all of the MovieLens dataset files, including the README, which contains licensing, citation, and other information. This solution may not work well if you’re using an online IDE and I apologize in advance for the inconvenience. Please let me know if you have any other problems with this example at [email protected].

Locating the Machine Learning for Dummies, 2nd Edition Source Code

A reader recently wrote to say that the source code for Machine Learning for Dummies, 2nd Edition on GitHub is incomplete. Actually, that wasn’t originally one of the download sources for the book’s code and we had used that site for an intermediary code location, so it wasn’t complete. The GitHub site code is complete now, but we’d still prefer that you download the code from one of the two sites listed in the book: On my website at http://www.johnmuellerbooks.com/source-code/ (just click the book’s link) or from the Wiley site at https://www.wiley.com/en-us/Machine+Learning+For+Dummies%2C+2nd+Edition-p-9781119724056 (just click the Downloads link, then the download link next to the source code you want). The two preferred sites offer the source code in either Python or R form in case you don’t want to download both.

When you get the downloadable source, make sure you remove it from the archive as described in the UnZIPping the Downloadable Source post. Using the downloadable source helps you avoid some of the issues described in the Verifying Your Hand Typed Code post. Please let me know whenever you encounter problems with the downloadable source for a book at [email protected].

Source Code Placement

This is an update of a post that originally appeared on October 12, 2015.

I always recommend that you download the source code for my books. The Verifying Your Hand Typed Code post discusses some of the issues that readers encounter when typing code by hand. However, I also understand that many people learn best when they type the code by hand and that’s the point of getting my books—to learn something really interesting (see my principles for creating book source code in the Handling Source Code in Books post). Even if you do need to type the source code in order to learn, having the downloadable source code handy will help you locate errors in your code with greater ease. I won’t usually have time to debug your hand typed code for you.

Depending on your platform, you might encounter a situation the IDE chooses an unfortunate place to put the source code you want to save. For example, a Windows System might choose the Program Files folder, which contains a space and doesn’t allow saving of files unless you specifically override the default rights. Fortunately, modern IDEs do manage to avoid many of these problems, but you still need to be aware that they could exist, especially when using an older IDE.

My recommendation for fixing these, and other source code placement problems, is to create a folder that you can access and have full rights to work with to store your source code. My books usually make a recommendation for the source code file path, but you can use any path you want. The point is to create a path that’s:

  • Easy to access
  • Allows full rights
  • Lacks spaces in any of the pathname elements
  • On a local drive, rather than a cloud drive in many cases

As long as you follow these rules, you likely won’t experience problems with your choice of source code location. If you do experience source code placement problems when working with my books, please be sure to let me know at [email protected].

Verifying Your Hand Typed Code

This is an update of a post that originally appeared on January 10, 2014.

I maintain statistics for each of my books that are based on reviews and reader e-mails (so those e-mails you send really are important). These statistics help me write better books in the future and also help me determine the sorts of topics I need to address in my blog. It turns out that one of the most commonly asked questions is why a reader’s hand typed code doesn’t work. Some readers simply ask the question without giving me any details at all, which makes the question impossible to answer. In some cases, the reader sends the hand typed code, expecting that I’ll take time to troubleshoot it. However, this isn’t a realistic request because it defeats the very purpose behind typing the code by hand. If I take the time to diagnose the problems in the code you typed, I’ll be the one to learn an interesting lesson, not you. If you learn better by doing—that is, by typing the code by hand and then running it, then you need to be the one to troubleshoot any problems with the resulting code.

My advice to readers is to use the downloadable source code when working through the book text. If you want to type the code by hand after that as part of your learning experience, at least you’ll know that the example works on your system and you’ll also understand how the example works well enough to troubleshoot any errors in your own code. However, you need to be the one to diagnose the errors. If nothing else, perform a character-by-character comparison of your code to the example code that you downloaded from the publisher’s site. Often, a reader will write back after I suggest this approach and mention that they had no idea that a particular special symbol or method of formatting content was important. These are the sorts of lessons that this kind of exercise provide.

Now, it has happened that the downloadable source code doesn’t always work on a particular user’s system. When the error is in the code or something I can determine about the coding environment, you can be certain that I’ll post information about it on my blog. This should be the first place you look for such information. Simply click on the book title in question under the Technical category. You’ll find a list of posts for that book. Always feel free to contact me about a book-specific question. I want to be sure you have a good learning experience.

There are some situations where a reader tries to run application code that won’t work on a particular system. My books provide information on the kind of system you should use, but I can’t always determine exceptions to the rule in advance. When I post system requirements, your system must meet those requirements because the examples are guaranteed to fail on lesser systems. If you encounter a situation where the downloadable code won’t run on your system, but none of the fixes I post for that code work and your system does meet the requirements, then please feel free to contact me. There are times where an example simply won’t run because you can’t use the required software or the system won’t support it for whatever reason.

The point of this post is that you need to work with the downloadable source code whenever possible. The downloadable source code has been tested by a number of people, usually on a range of systems, to ensure it will work on your system too. I understand that typing the code by hand is an important and viable way to learn, but you should reserve this method as the second learning tier—used after you have tried the downloadable source code. Please let me know if you have any questions or concerns at [email protected].

Working with Code in e-Books

This is an update of a post that originally appeared on March 16, 2016.

Most of my technical readers now use e-books instead of paper books. Of course, there is a convenience factor to storing your entire library on a Kindle, even if it’s a software version of the Kindle. Of course, there are all sorts of e-book formats for your desktop system as well. The point is that electronic format makes a lot of sense when dealing with technical books.

However, e-books can cause some interesting problems and I’ve encountered a few with a number of readers now. The most important consideration is that you can’t cut and paste code from an e-book directly into your IDE and expect it to work. There are all sorts of reasons for this exclusion. For example, cutting and pasting may insert special characters into the output stream or the resulting paste may not have white space in the right places. A common problem is that publishers often convert regular single and double quotes into curly quote equivalents. The two kinds of quotes (both single and double) are completely different and the second type definitely won’t compile.

The best option when working with an e-book is to view the code in the e-book, but still get the downloadable source code for the book from my website or the publisher’s website as described in the book’s introduction. If you can’t find the downloadable source, always feel free to contact me at [email protected]. I want to be sure you have a great reading experience, which means having source code that actually runs in your development environment.

Another potential problem with e-books is that you may see unfortunate code breaks (despite the efforts of the publisher and myself). When you need to understand how white space works with a programming language, always review the downloadable source. The fact that the downloadable source compiles and runs tells you that all the of white space is in the right place and of the correct type. Typing the source code directly out of your e-book could result in added carriage returns or other white space errors that will cause the code to fail, even though the commands, variables, and other parts of the code are all correct.

As always, I’m open to your questions about my books. If you don’t understand how things work, please contact me—that’s why I’m here.

UnZIPping the Downloadable Source

A number of readers have written me to say that they are using the downloadable source and can see the files on their hard drive. However, when they go to access the file using their IDE, the IDE won’t open it. Modern operating systems make things easier for people by displaying the contents of .zip and other archive files as if they’re another directory or folder on the system. However, the IDE doesn’t have the same advantage. You need to remove the files from the .zip archive and place them somewhere on your hard drive that the IDE can locate. You can tell that you’re looking at a .zip file by looking at the path. If you see something like C:\Temp\A4D2E.zip\A4D2E, where A4D2E.zip is the name of the archive, then you know that you’re looking in an archive file. If you still have problems getting the files to open, make sure you remove any spaces from the path that your IDE is using. You can contact me at [email protected] if you have any additional questions about this issue.

Python for Data Science for Dummies Errata on Page 221

The downloadable source for Python for Data Science for Dummies contains a problem that doesn’t actually appear in the book. If you look at page 221, the code block in the middle of the page contains a line saying import numpy as np. This line is essential because the code won’t run without it. The downloadable source for Chapter 12 is missing this line so the example doesn’t run. This P4DS4D; 12; Stretching Pythons Capabilities link provides you with a .ZIP file that contains the replacement source code. Simple remove the P4DS4D; 12; Stretching Pythons Capabilities.ipynb file from the archive and use it in place of your existing file.

Luca and I always want you to have a great experience with our book, so keep those emails coming. Please let me know if you have any questions about source code file update at [email protected]. I’m sorry about any errors that appear in the downloadable source and appreciate the readers who have pointed them out.

 

Python for Data Science for Dummies Errata on Page 124

Python for Data Science for Dummies contains an error in the example that appears on the top half of page 124. In the first of the two grey boxes, the code computes the results of four print statements. The bottom-most print statement, print x[1:2, 1:2], is supposed to compute a result based on rows 1 and 2 of columns 1 and 2, and the bottom grey box seems to confirm that interpretation by the showing the result as [[[14 15 16] [17 18 19]] [[24 25 26] [27 28 29]]]. However, the answer provided for this example in the downloadable source code is [[[14 15 16]]], which doesn’t agree with that in the text.

The good news is that the downloadable source contains the correct code. The error appears only in the book. The last print statement in the book is wrong. Here is the correct code (with output) for this example:

x = np.array([[[1, 2, 3], [4, 5, 6], [7, 8, 9],],
 [[11,12,13], [14,15,16], [17,18,19],],
 [[21,22,23], [24,25,26], [27,28,29]]])

print x[1,1]
print x[:,1,1]
print x[1,:,1]
print
print x[1:3, 1:3]
[14 15 16]
[ 5 15 25]
[12 15 18]

[[[14 15 16]
 [17 18 19]]

[[24 25 26]
 [27 28 29]]]

Please let me know if you have any questions about this example at [email protected]. I’m sorry about the error that appears in the book and appreciate the readers who have pointed it out.