book2 | Sample game code repository for my book vol.2

Say I have an array of 5 objects, each with 2 keys (eg, 'title' & 'author').

I want to check the truthiness that 3 SPECIFIC titles exist in the array.

What's the best way to do that?

I have the following... but it doesn't seem very efficient:

I’m using Gremlin for querying a Graph DB and I’m having trouble figuring out how to retrieve all properties of a specific vertex along with all properties of specific child vertices. I know valueMap() is generally the operation to use to expose properties of nodes, but I'm not sure I am using it correctly.

Here is a visual representation of the Graph that I am working with. In this graph there are author nodes, which can be related to multiple book nodes connected by a wrote edge. And a book node can be connected to multiple chapter nodes by a hasChapter edge. A book node has a title and year as additional properties, while a chapter node has a name and a length as additional properties:

Here is the data that produces the above graph:

I want to make an abstract class, A that will be subclassed by Class B and Class C such that they will all use the same methods in the defined abstract class (B and C are A-able classes).

I have another class, Z, that will contain an array of A-able classes. I would like for it to have a function that allows it to swap between B and C in that array (ie. calling initializer/member function with an argument).

The below example, while not being exactly like what I'm describing above (not using abstract classes), showcases the same issue I'm running into: I'm unable to set the array to the correct subclass, since it's complaining that it was initialized as the parent class.

However, this should be possible to do right? What am I missing here?

I have an excel file that looks like:

I would like to read this into pandas dataframe and avoid getting NAN values. The reason I am trying to avoid getting NAN is that later on, I want to create a simple contingency table similar to this

and NAN values create issues in this contingency table. Is there any elegant way of doing this without reading columns separately, using value_counts(), and concatenating the series, as below?

I'm using GemBox.Spreadsheet to process some Excel files, now I need to combine them into one file with one sheet.
I know how to do sheets copying, but that will result in multiple sheets. What I need is a single output sheet that will contain all of them, one after another.

Currently what I'm doing is I export each sheet as a DataTable and then import it one by one:

I'm starting with this DataFrame:

I am trying to create an ul which has a li for each review in the Set reviews from the book object that I send back from the server. The result is seemingly a massive internal server error, I get a very long stack-trace printed out to the terminal, I have no idea what might be the problem. If I comment out the ul block, everything works fine.

The error (opens new link, pastebin) (not the full error, it did not fit in VSCODE terminal.

book.html

I have a following problem. I am doing association rules mining using efficient_apriori package in python. I would like to save my rules as pandas data frame. See my code:

I have a dataframe as below: