startfrom | Github repo as a template for a new project | Runtime Evironment library

My goal is that when I create an instance of my mother class, this instance should appear as a PictureBox in my form.

To add something to a form you need to actually add it. To add a control to a container you would call myPanel.Controls.Add See Control.Controls. If you want this to happen when you create your object you could do this in the constructor, taking the container as a constructor argument.

I would however argue that this is not a great design, There is the Composition over inheritance principle that suggest that components will be more flexible and reusable when inheritance is reduced. It is usually recommended to use one of the patterns to separate the domain model from the UI, like MVVM, MVC, MVP.

A more modern design would be to have a list of all the animals you want to show, and map this to the UI, so that adding or removing animals is reflected list of images in the UI. In WPF this is fairly easy, you create an observable collection and some xaml code to bind a listview to this collection. In winforms you will have to do some of this work yourself instead.

Method appendTo attaches element to a a new parent. One element can't have two parents at once so in effect elements will be moved from firstMergedElement to secondMergedElement.
If you want to keep them also in firstMergedElement you can clone each of them:

Well, as you want to stick on this non-XML data and don't give us more information about the size of the data nor the way to reply if no number is next to the searched item then you could just start off with a simple regular expression like this one.

Regular expression: Four[\s-]*(\d*)

Play arround with it here: https://regex101.com/r/p0aaGG/1
You'll have the explanation of the regular expression on regex101.com:

• In PHP, a regular expression must be surrounded by a starting and ending char and then some flags can be added after. Most often we use the / delimiter like it's the case in JavaScript. But some persons use # or ~. Example:
  • /Teddy/i will look for the word Teddy but case insensitive.
  • ~Teddy~i is exactly the same regular expression but written with another delimiter. This is why preg_quote() has a second parameter to give the delimiter used if its not the usual slash /.
• \s means any kind of space char.
• [\s-] means any kind of space char or the - char.
• [\s-]* means it can be 0 or multiple times.
• \d means any digit char.
• \d* means any digit char 0 or multiple times.
• () are used to capture, so that we can get it later in the $matches array.

Now if , and Four are parameters then you could do this in PHP:

The correct way to store the data about a single entity (say "user") is to put it all in one table. A million rows is not a very large number of rows for modern databases. That should be the starting point for your optimizations.

In all likelihood, you just need the correct indexes on the table.

It looks like you have an ordering for the tiers. This information should be stored in separate reference tables.

Multiple tables are a bad idea for many reasons, including:

• SQL is optimized for fewer large tables rather than large numbers of smaller tables.
• Accessing all the data is quite tricky, because you need to union zillions of tables together that might change over time.
• Adding or modifying columns is tricky, because you have to change zillions of tables.
• Optimizations are hard to come by, because the data in each table is relatively small. The overhead of reading half-empty data pages might come to dominate your queries.

I would suggest that you learn about or review the principles of normalization and start over with your data model.

SingleOrDefault will throw an exception when more than one results get returned.

Enumerable.SingleOrDefault Method

Returns the only element of a sequence, or a default value if the sequence is empty; this method throws an exception if there is more than one element in the sequence.

You can try to use FirstOrDefault which will not mind if there are more than one result, it will return the top 1 in the results

Solution:

You have to work with SpecificClass

Apply some straightforward optimizations:

• list numbers should not be used because each number can be calculated based on an index
• simplified initialization of Isprime.

For 1'000'000 got:

You should try something like this instead. The query_string and the range queries need to be combined into a bool/filter query: