data-structures | provide insight into data structures

I'm learning a bit of JavaScript, but I'm having hard time understanding the lesson on FreeCodeCamp about the recursion countdown (link).

In the lesson, there this initial example. But I'm confused on how it operates:

How can I call in batch a multiple level of array ?

I want to create an array of unique value with multiples data, then I will manage to make an associative array after unyfing the values.

I have a csv file with lot of value like this :

this is a very small piece of code taken from this book about the Dijkstra Algorithm in Ruby: I think I can't post the entire example for copyright issue, so if you want you can download the source code from the above link of the book, the file will be in the folder jwdsal2-code\code\connecting_everything_with_graphs\dijkstra.rb. - it runs perfectly and there isn't any error in the code.

The excerpt from the code is the following:

Hi there I'm trying to create a small tool that will create child directory's within the Root directory

Root Dir(python) And child Dir(DS, WEB, Flask, Learn) stuff like that

At starting I have done it statically Here is the Code

I'm trying to display a stacked bar chart on my web page, but it's not working.

I've tried to follow the documentation about data structure, but it seems not working. The two data are made from an Ajax call and built in js.

https://www.chartjs.org/docs/latest/general/data-structures.html

I've made a jsfiddle if you want to look at what I've done.

https://jsfiddle.net/batmine3/h4w02y5g/6/

I was studying DMA proxy and DMA proxy channels. Basically they are like letting Userspace application to write tx, read rx kernel data-structures. and let the device to access virtual memory data structures since devices understand physical addresses.

This code https://github.com/mstuehn/dma_proxy/blob/master/dma_proxy_test.c

and this article that I am reading https://xilinx-wiki.atlassian.net/wiki/spaces/A/pages/18842418/Linux+DMA+From+User+Space

And from this Thesis http://www.diva-portal.org/smash/get/diva2:22746/FULLTEXT01.pdf it says this

in Linux the kernel uses virtual memory address but most hardware systems use physical address for bus addressing. For hardware to be able to access data structures residing in kernel virtual memory space these structures have to be mapped to physical memory address. Its not sufficient to use simple address conversion methods since some system memory management unit have to be re-programmed and bounce buffers have to be used (probably in system memory management unit -- please clarify).

I think I have some grasp of dma proxy drivers and associated Userspace application(What I am guessing is it is used in embedded Linux systems).

But What's the point of all of this for example if I am looking at NIC card, then whatever I suppose to get with the mmap call in Userspace application and Kernel implementation of MMAP in proxy driver will have kernel data structure. in case of NIC card the RX/TX will be the device specific data structures representation in kernel memory space since geting struct ethhdr / struct iphdr / struct tcphdr / etc. from return of mmap is not possible since the above paragraph from thesis says conversion of virtual addresses to Userspace addresses is probably not possible (basically it says physical address. I am assuming this from the text read )

So basically I am not fully getting the use of dma proxy drivers. I need some explanation to clear this out and how can the return of mmap calls be used in applications i.e. server applications in embedded Linux systems

I have the following list:

I'm trying to subclass pandas data structure. If I set a field on the instance, it works fine.

I'm working on a min heap implementation and am really new to the concept.

Using this as reference:
https://www.geeksforgeeks.org/building-heap-from-array/
https://algorithmtutor.com/Data-Structures/Tree/Binary-Heaps/

I modified the code and came up with:

(this is the code I'm having problems with, all other code is irrelevant to my problem, at least so I think)