rand | A Rust library for random number generation | DevOps library

I have updated IntelliJ Idea Ultimate and scala plugin, it's working ok so far with sbt to build some projects.

Using a scala worksheet in REPL Interactive mode, I put in some code from a course lecture,

I'm wonder how can I undo my transpose operation. Let me be more specific in example:

I have a dataframe where I want to group rows based on a column. Some of the columns in the rows I want to sum up and the others I want to aggregate as a list.

I've written this code down here but my problem is whenever i hit the run button and execute my program the values are fine but every element of the 2D array is printed out in a separate line, it's not printing a square with area its dimensions (size n x n) like i wanted, how can i fix this?

my code

it should be like this what i want it to look like

I'm trying to figure out the behavior of for(i = 0; i < rand(); ++i) where I'm not sure if the second expression is supposed to generate a new random number each time the loop iterate or just when it executes for the first time.

Tried to find out by comparing the program execution times but no luck as there were no big differences between them.

Does the random number generates once or each time the loop iterate?

I'm trying to make a small simulation of traveling salesman in Unity C# and I can't get through this, my code looks right but start and nxtCity vectors always result in the same position, I really can't understand why, could any of you help?

cities is the number of total cities

positions is the array of cities taken from cities generator these two values are right in unity editor

Here the code:

I'm trying to create a random ID generator, my problem is I don't know how to check if it already exists. I have a std::vector which I use to store the IDs (Client is my class):

I'm creating an int (32 bit) vector with 1024 * 1024 * 1024 elements like so:

I have a dataset with several variables like the one below: