Eduardo Jiménez's questions

I have a JSON with a format similar to this:

[{
  "email": "[email protected]",
  "school_id": 1,
  "school": "Escuela 1"
}, {
  "email": "[email protected]",
  "school_id": 1
  "school": "Escuela 1"
}, {
  "email": "[email protected]",
  "school_id": 1
  "school": "Escuela 1"
}, {
  "email": "[email protected]",
  "school_id": 2,
  "school": "Escuela 2"
}];

And I would like to create a New JSON that joins the school_id and school properties into a new property called schools which would be an array of[{school_id: number, school: string}]

I would like to make use of functional programming, however, I still can't find the correct way to achieve this:

[{
    "email": "[email protected]",
    "schools": [{
        "school_id": 1,
        "school": "Escuela 1"
      } {
        "school_id": 2,
        "school": "Escuela 2"
      }
    },
    {
      "email": "[email protected]",
      "schools": [{
        "school_id": 1,
        "school": "Escuela 1"
      }]
    },
    {
      "email": "[email protected]",
      "schools": [{
        "school_id": 1,
        "school": "Escuela 1"
      }]
}];

So far I have tried this:

let results = [{
  "email": "[email protected]",
  "school_id": 1,
  "school": "Escuela 1"
}, {
  "email": "[email protected]",
  "school_id": 1,
  "school": "Escuela 1"
}, {
  "email": "[email protected]",
  "school_id": 1,
  "school": "Escuela 1"
}, {
  "email": "[email protected]",
  "school_id": 2,
  "school": "Escuela 2"
}];

results.forEach((result, idx) => {
  if (results.findIndex(el => el.email === result.email) > idx) {
    result.schools.push(results.filter((el, index) => el.email === result.email && index > idx));
    delete result.schools.email;
    delete result.school_id;
  } else {
    result.schools = [{
      school_id: result.school_id,
      school: result.school
    }]
    delete result.school_id;
    delete result.school;
  }
});
console.log(results);
console.log(JSON.stringify(results));

The idea is that from any list Objectin java, the mode of the elements can be obtained. This means ALL the elements that have the same and maximum frequency.

The example is the following list:

ArrayList<Object> strings = new ArrayList<>(
        Arrays.asList("hello", "world", "my",
                "world", "is", "you", "and",
                "your", "world", "is", "me",
                "is", "love", "this", "?")
);

Where we see that the words are repeated 3 times: " hello " and " is "

The result should be something similar to:

I had a question about why the term character is ignored when sending a sequence of characters to STDOUT .

For example, in C when you do the print

printf("%s", "hello\0world");

The output reaches \0, since it is the character that indicates that the sequence of characters ends there, that is, it only printshello

However, reproducing this same behavior in Java only ignores this character

public static void main(String... args) {
    char[] hello = {'h', 'e', 'l', 'l', 'o', '\0', 'w', 'o', 'r', 'l', 'd'};
    System.out.println(hello);
    System.out.println("hello\0world");
}

and the output is helloworld, Why is this happening? Is it a compiler issue?

If the compiler is not involved, then how does it distinguish which is the true term character?

What I need is to add in a single statement all the lengths of an array which is a property that is found in all the JSON of a JSON array.

Let's take the following json as an example:

[
    {
      id: 1,
      element: [1, 2, 3]
    },
    {
      id: 2,
      element: [5]
    },
    {
      id: 3,
      element: []
    }
]

The statement should add [1, 2, 3].length + [5].length + [].lengthwhich should give 4. The problem is that I need to do it in a single statement, but I haven't been able to do it, I tried with reduce but it's not clear to me how it works.

const array = [
    {
      id: 1,
      element: [1, 2, 3]
    },
    {
      id: 2,
      element: [5]
    },
    {
      id: 3,
      element: []
    }
];

console.log(array.reduce((accumulator, current, idx) => accumulator + array[idx].element.length));

console.log(array.reduce((accumulator, current) => accumulator + current.element.length));

I am working the commits through SSH keys, the process I do to identify myself is the following:

eval $(ssh-agent)
ssh-add ~/Desktop/ssh/Github/UsuarioA  <--- Llave privada

Even if I run the command

ssh -T [email protected]

It appears that I identified myself as user A: Hi UserA ! You've successfully authenticated, but GitHub does not provide shell access.

But when making commits it appears to me that they were made by UserB !

What seems most strange to me is that I have already deleted the keys of UserB, they do not exist. And the repository is private and UserB does not have permission to access that repository. I don't understand what is happening, because there are no warnings or errors, any idea what is happening?

Note: I use GitBash for it and work with Windows

Problem image:

For my project I need to query with LIKE . Reading the part of optimazing like it only mentions that optimizer_use_condition_selectivity should be used , however, the documentation is not very clear to me. I don't understand what should be done or how that optimization should be applied; So far it seems like a flag to me. But of what?

Also reading this other article (But SQL not MariaDb) recommend creating an index in this way.

CREATE NONCLUSTERED INDEX SK01_Test_Collation_SQL ON table_name (column_name) WITH(FILLFACTOR=90)

Should I get one for my table too or would the above be enough? How would it be for MariaDb in that case?

As additional information, this is what my table looks like (I removed all the foreign keys) and the query will be on the title column .

DROP TABLE IF EXISTS Thesis_Detail;
CREATE TABLE Thesis_Detail(
    thesis_id INT UNSIGNED PRIMARY KEY NOT NULL AUTO_INCREMENT,
    title VARCHAR(255) NOT NULL,
    file VARCHAR(255) NOT NULL,
    abstract TEXT NOT NULL,
    uploaded_datetime DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
    INDEX(title)
) DEFAULT CHARACTER SET utf8mb4;

There are languages ​​like javascript which accept that their functions have a default value. For example:

function times(number = 3, mult = 2) {
    return number * mult;
}

times();                // --> 6
times(5);               // --> 10
times(undefined, 4);    // --> 12
times(5, 3);            // --> 15

Is it possible to achieve this behavior in Java?

I am trying to forcefully accommodate text and images in the indicated order , however in the sheet changes if the image does not fit but more text does, Latex fills that space with the following text, that makes it not follow the order that I want to achieve. It would be very helpful if you could guide me, thanks!

I went through this documentation , however I couldn't achieve what I wanted

Here's an example of how I'm arranging things

\begin{tabbing} 
    Obtenemos:
    \= $ equation$ \\
    \> $ equation$ \\
\end{tabbing}

\begin{figure}[!h]
    \centering
    \includegraphics[height=0.5\textwidth]{img.png}
    \caption{Circuito equivalente de la figura~\ref{fig:circuit2-1}}
    \label{fig:circuit2-2}
\end{figure}
                
\begin{tabbing} 
    Partiendo de~\ref{fig:circuit2-2} tenemos:
    \= $ equation$ \\
    \> $ equation$ \\
\end{tabbing}

\begin{figure}[!h]
    \centering
    \includegraphics[height=0.5\textwidth]{img2.png}
    \caption{Circuito equivalente de la figura~\ref{fig:circuit2-2}}
    \label{fig:circuit2-3}
\end{figure}