blackbird | Blackbird Bitcoin Arbitrage : a long/short market | Cryptocurrency library

I need help with heatmaps, I am first timer and I usually have problems when coming to frequencies graphs.

I need to create a heatmap with date on x axis, and crepus on y axis. That is fine.

The variable I want for the color is the frequency of all species (speciesname), which would be the total sum of all species of the variable nmb_individuals, obviously by date and crepus value.

When trying it, I get a completely blank heatmap, though the scale looks good:

I have data that I want to convert to lowercase and separate with underscores using snakecase::to_any_case(). However, I wish to ignore cells that contain either TRUE/FALSE and keep them as uppercase.

for making a reproducible example

I wrap a QAbstractTableModel instance in a QSortFilterProxyModel in order to be able to sort and filter it. Sort requests sort column data as strings - instead I want the columns to be sortable by their appropriate datatype.

There are a handful of questions/answers on the site that speak roughly about this problem, but none provide a contained solution to the 'sort appropriate data type' problem for a table where the need is to be able to sort any column by the method appropriate for its datatype.

By appropriate sort method, I mean I want the QSortFilterProxyModel to sort integer columns as integers, sort float columns as floats, sort date columns as dates, and sort string columns as strings (well, the string kind, it already handles...).

There seem to be one or two ways suggested to accomplish this. One involves setting up your source model to have its own SortRole that, for example, sort a column by integers. Can that implementation be tweaked to sort a column by it's 'native' datatype rather than pre-prescribing a SortRole for each column?

In my specific use case, the source model is actually a pandas dataframe model. This is worth noting because perhaps conveniently, each of my columns DOES have a native/built-in/reliable datatype that could be known progammatically. Hence if it made implementation easier, I would forego the ability to sort a single column with many different datatypes*, to receive the ability to sort by any column by the correct method for its datatype. (*I realize there are cases where that ability is useful and appreciate that is perhaps what the default behavior agnostically addresses, but I have no immediate need for it.)

Another solution I've seen discussed either by itself or in conjunction with special roles, involves reimplementing the QSortFilterProxyModel class and overloading the lessThan function. This solution makes sense to me, I just haven't been able to find an example where a clean implementation of this is done that can apply the appropriate sort method for the data based on the datatype of data it's sorting. Those solutions all seem to rely on a hardcoding a method for a column. It seems like there should be away to handle that 'column-sort method' lookup programmatically either on the fly as the lessThan method is called, or at least each time the sourcemodel refreshes.

See end of post for the minimal reproducible example.

Or see these snippets:

I have a BTO dataset, which I converted from long to wide format to prepare it for diversity measurements using the diversity function from the vegan package.

To achieve this I used this code:

I'm trying to plot shannon diversity for BTO data, however, to use the vegan package, I must place the data into matrix form. This is not a problem, however, I have various variables to group shannon diversity by however, I'm having difficulties subsetting this into code.

I need a way to calculate diversity by localicity_id + Postcode + week + year, using this code:

working with django 3.0.5, but i guess this relates also to < django 2.0.

I uploaded my first django app on my providers space, so far everything works. This is a Server Schema of my Provider...

I try to sort a complex structure of case classes according to a certain criterion, which has several (a finite number) characteristics. The sorting should be done according to a ranking list.

Explained by following example: I have artifacts with a field bird which can have the expressions blackbird, starling, raven, budgie as string. A sequence should be sorted in the order (not alphabetically)

1. starlings
2. blackbirds
3. budgies
4. ravens

The birds themselves may have dependencies on each other, so the order within the groups must not be changed.

What I tried so far was to first group them, then sort the groups and patch them back together. Yet it looked clumsy and two questions arose:

1. Will groupBy always keep the previous order? By looking at the ScalaDoc ref, it looks to me that it will.
2. Is there a more efficient/not so clumsy way to sort the groups then the following:

edit: added a complete example, fixed an issue

I used a combinator to calculate the average of a list of numbers...

const myCombinator = f => g => h => x => f(g(x))(h(x));

I could then use it like...

I haven't programmed in Prolog for years and am struggling with a simple block of test code (I'm trying to solve a logic puzzle for fun...):