excellent | Source Code analysis gem for Ruby and Rails | Application Framework library

I have the following two data.frame. I want to get the Grade from D1 and Assign to the Pts in D. Once the operations completes the D data.frame should have a columns for Pts,Val, and Grade without C or Good Grade.

I'm stuck on a problem with writing a parser in Haskell that I hope someone can help out with!

It is a bit more complicated than my usual parser because there are two layers of parsing. First a language definition is parsed into an AST, then that AST is transformed into another parser that parses the actual language.

I have made pretty good progress so far but I'm stuck on implementing recursion in the language definition. As the language definition is transformed from AST into a parser in a recursive function, I can't work out how it can call itself if it doesn't exist yet.

I'm finding it a bit hard to explain my problem, so maybe an example will help.

The language definition might define that a language consists of three keywords in sequence and then optional recursion in brackets.

I am having a problem understanding how CSS grid works.

I want 3 columns side by side with a specific width and height, but there's a gap between each columns.

I'm working to get a better handle on pivot_longer, coming from a gather user. From the source documents it seems like I should be able to do the following in a single command using name_pattern or names_sep but I've been unable to find a working solution.

Data

I am currently trying to learn Kotlin with the help of the book "Kotlin Programming The Big Nerd Ranch Guide" and so far everything worked. But now I am struggling with the "lazy" initialization which throws a NullPointerException which says

Cannot invoke "kotlin.Lazy.getValue()" because "< local1>" is null

The corresponding lines are:

I have a MultiIndex data frame called df with 3 indexes (Fruit, Color, Taste). I want to search 1 specific index, that index being Color and see if the value exists in it.

For example: the code would look something like this. Color is an index in the dataframe not just a column.

Just for context, I've got a Git repo with a number of remotes, some of which I consider less important and put in a subgroup by prepending them with a group name and a slash. For example, I might have origin, othercomputer as my "main" remotes; and otherpeople/alice, otherpeople/bob as secondary remotes that I just check in on occasionally. I was looking for a simple way to make gitk only list branches in my main remotes (since gitk --all lists everything).

Just as a random thing, I tried running gitk \*, and frankly to my surprise, it seems to have done exactly what I was looking for (displaying my local branches and my "main" remotes), so I tried to figure out what it actually does. Since the arguments to gitk are mostly the same as those to git rev-list, I've been trying to read that manpage in order to do that, but I can't find anything.

So, what does gitk \* do, and where is this documented? (I assume that it is documented, since Git documentation is generally quite excellent.)

(Just to avoid confusion, the backslash in \* is the shell escape to pass the asterisk unmodified to gitk. I did not mean to imply that I'm actually passing that backslash to gitk.)

So I decided to tryout functional programming because people say it gives you more control over the programs that you write, it's extremely testable, and it makes code more readable & easy to follow — who wouldn't want that..?

Obviously I decided to try writing a program using the functional paradigm. I got stuck, nearly just as soon as I decided to try writing the thing. I couldn't really figure out how to make all of the program's data immutable. My first thought was to use all const declared variables, since a const variable cannot be re-referenced after the initial assignment, however; I found out that implementing an immutable data structure is quite different from declaring several const variables to store a programs state in. It became quite clear to me that I was going to need immutable objects, with immutable properties, and so forth. After attempting to create an Immutable data structure (example is at the question's bottom). I concluded that that JavaScript doesn't really have a way of implementing Immutable data, at least not a way that is obvious. And now here I am, scratching my head...

What I would like to know is:

"How are the people, who are writing JavaScript programs, using the Functional Programming paradigm implementing immutable data structures when the language doesn't really offer any sort of way implementing immutability?

EDIT: I want to be as clear as possible, because I have struggled with clarity in some of my past questions, so I am just going to sorta meta-explain what I am asking for:

In a nutshell, what I would like to know is: How does a person implement immutable data structures that work for the functional programming paradigm. An example of Any immutable data structure will suffice, or even an immutable object. If the answer involves use 3rd party libraries, other languages, or any other tool that would be great, and an example of what code using those tools might look like would be really excellent.

Below is some code, where I was trying to hack a JS object into being immutable. Its not good code, in fact it throws an error, but it demonstrates my mindset, and what I am trying to solve.