fst | Lightning Fast Serialization of Data Frames for R | Machine Learning library
kandi X-RAY | fst Summary
kandi X-RAY | fst Summary
The fst package for R provides a fast, easy and flexible way to serialize data frames. With access speeds of multiple GB/s, fst is specifically designed to unlock the potential of high speed solid state disks that can be found in most modern computers. Data frames stored in the fst format have full random access, both in column and rows. The figure below compares the read and write performance of the fst package to various alternatives.
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QUESTION
A bit of background:
I am an amateur programmer, having picked up Haskell a few months ago, on my spare time, after a period of Mathematica programmning (my first language). I am currently going through my second Haskell book, by Will Kurt, but I still have miles to go to call myself comfortable around Haskell code. Codeabbey has been my platform for experimentation and learning so far.
I have written a piece of code to generate permutations of a given number, that deals with possible duplicate numbers, so for 588 it will internally generate 588, 858 and 885.
However, because I want to scale to pretty big input numbers (think perhaps even a hundred digits long), I don't want to output the whole list and then perform calculations on it, instead every number that is generated is checked on the spot for a certain property and if it has it, well, we have a winner, the number is returned as output and there's no need to go through the rest of the humongous list. If sadly no desired number is found and we unsuccessfully go through all possible permutations, it outputs a "0".
I have also opted to make it a command line program to feed values to it via gnu parallel for faster work.
So here is the code
...ANSWER
Answered 2021-May-09 at 12:17So I am not 100% sure of this and I am also not 100% sure I understand your code. But as far as I understand you are generating permutations without duplicates and then you are checking for some predicate wanting whatever single number that fulfils it.
I think it should help to use as many of the prelude functions as possible because afaik then the compiler understands it can optimize recursion into a loop. As a rule of thumb I was taught to avoid explicit recursion as much as possible and instead use prelude functions like map
, filter
and fold
. Mainly you avoid reinventing the wheel this way but there also should be a higher chance of the compiler optimizing things.
So to solve your problem try generating a list of all permutations, then filter it using filter
and then just do take 1
if you want the result that is found first. Because of Haskell's lazy evaluation take 1
makes it so that we are interested only in the first x
in (x:xs)
that a filter
would return. Therefore filter
will keep dropping elements from the, again lazily evaluated, list of permutations and when it finds one it stops.
I found a permutation implementation on https://rosettacode.org/wiki/Permutations#Haskell and used it to try this call:
QUESTION
I am a total script kitty at best and am trying to use google apps scripts to automate a process for me. Here a sample table like the one I am working with(data is in google sheets spreadsheet):
Variety Category Peter Courtney DP HBC 0.00 4.5 DP MNG 2.00 0 UB THN 7.00 0 471H THN 5.00 0 471H THN 0.00 5 GRH FST 4.00 0 GRH THN 8.00 0 GRH THN 0.00 8 GRH THN 0.00 8 HM HBC 6.50 0 HM HBC 0.00 6.5 HM MNG 2.00 0 HM MNG 0.00 2 CL HBC 8.50 0 CL HBC 7.00 0 PSV HBC 2.50 0 PSV HBC 7.00 0 PSV HBC 0.00 2.5The table shows the employees reported hours broken down by Variety and category. My goal is to compile this data so if the employees work at the same category and same variety I want all hours expressed in a single line. For instance if you look at the last two rows of the data you'll notice that the Variety and Category columns are matching which means the data should be compiled. So instead of:
Variety Category Peter Courtney PSV HBC 7.00 0 PSV HBC 0.00 2.5I want to compile the data like this:
Variety Category Peter Courtney PSV HBC 7.00 2.5I am trying to do this from the bottom up because I heard going from the top down can cause issues but I am open to any suggestions. I think I need to write a for loop that compares the variety box of the active row to the variety box of the above row AND compares if the category box of the active row is equal to the category box of the above row and if both are true add the hours of both the "Peter" column and "Courtney" column.
I know there is more to do on top of that but this for loop is what I really need help on, unless you can suggest a better way?
Thanks for looking at my work, JP
Stackoverflow member Ruben has asked me to elaborate more, here is where I am at:
I found a stackoverflow answer that pushed me in the direction of how to parse the data with the for loop. Here is the for loop skeleton I am working with:
...ANSWER
Answered 2021-May-28 at 13:43If you are open to using a formula instead of script, I can propose a solution. (In my own practice of decades, I save script for only those times when formulas cannot produce the desired result; this cuts down greatly on potential problems.)
This solution uses information from the script in your post to ascertain that the name of the source sheet is 'gest' and the ranges of data to include in the new report are B:C and E:F.
Create a new sheet and place the following formula in cell A1:
=ArrayFormula({gest!B1:C1, gest!E1:F1; QUERY({gest!B2:C, E2:F},"Select Col1, Col2, SUM(Col3), SUM(Col4) WHERE Col1 Is Not Null GROUP BY Col1, Col2 LABEL SUM(Col3) '', SUM(Col4) ''")})
This single formula will produce all headers and results, and will "keep up" as you add new rows of data in the 'gest' sheet.
A virtual array is formed between the curly brackets { }. This is a way of "sticking together" non-contiguous data in new ways.
The headers are grabbed by the two references preceding the semicolon.
Then a QUERY
is formed from the non-header information in the target columns.
In plain English, the Select
clause of the QUERY
reads "Return four columns: exactly what is in the first requested column and the second requested column followed by the categorized sums from the third and fourth requested columns, separating (i.e., "GROUP
ing") those sums by each unique pairing from the first two columns." The LABEL
section just removes technical headers from the sum columns created (which would otherwise have placed stock headers of 'sum' above each of the summed columns).
QUESTION
I have wrote this Inductive predicate and part of the proof for its (strong) specification:
...ANSWER
Answered 2021-May-24 at 02:51You could put a pair in the result, e.g.:
QUESTION
I have a asp.net application, where I wanted to use a premade bootstrap template for my frontend. I found this one. The original site from the template looks really nice with a background like this:
I copied all the css into my css folder, and also took the html and cut some parts of it out such that I could just render my own content in it.
My _layout.cshtml
that should be a scaffolding for other html files looks now like this:
ANSWER
Answered 2021-May-22 at 23:53Is your mentioned path (../../wwwroot/assets/home-bg.jpg) correct? because image won't be rendered if path is incorrect, and the background color becomes grey because of the classname mentioned.
QUESTION
I wanted to create a method, that interprets this List (The method "words" splits a String into a list of words, that are seperated by \s.) in postfix-notation. This is what I got, by I am wondering if there is a shorter way to solve this, as I am repeating myself quite often there.
...ANSWER
Answered 2021-May-17 at 15:11What I did
- I replaced the
if
-else
statement withswitch
-case
(I do not have to usebreak
, because Ireturn
. - I removed unnecessary
else
-statements (don't use them if you already returned in theif
-statement). - I extracted a method called "evalSingle" (you have to replace ??? with whatever
add
,sub
... are).
Code
QUESTION
I want to change terminal/taxa colour to blue, for specific taxa.
I'd like to change "Pomquet Lake", "Lake Ainslie", "Black River", "Pinchgut Lake", and "Blue Pond" to blue. is there a way to do this?
Code (figure below):
...ANSWER
Answered 2021-May-13 at 15:52No data are given, so that the example is not fully reproducible. The following general example using hclust
may hopefully give you an idea:
QUESTION
#!/bin/bash
ctime=
date +%s
# returns 1618634997 to $ctime
stime=$(wget --server-response --spider http://www.server.org/news_32.mp3 2>&1 | grep -i Last-Modified)
# returns : Last-Modified: Sat, 17 Apr 2021 04:49:57 GMT
# into the variable $stime
I need to convert $stime
to epoch time, put it in $etime
to compare them, and decide to download file, or not.
Need some code to manipulate the string.
to do date comparison
...ANSWER
Answered 2021-Apr-21 at 09:57Try the following:
QUESTION
I'm working in Cubical agda and trying to build up some common utilities for later proofs. One of these is that for any type A
it is the 'same' as the type Σ A (\_ -> Top)
where Top
is the type with one element. And the issue is how to best expose this 'sameness' from the utility library. I can expose it as an equivalence, a path or an isomorphism, and maybe multiple ones.
I originally exposed it as just a path: top-path : Path A (Σ A (\_ -> Top))
which is built up using glue types from an underlying top-equiv : A ≃ Σ A (\_ -> Top)
. But when trying to use this in later proofs I found out that transporting along this path did not compute as I expected. My expectation was that it composed with fst
to the identity, but in practice I found that it sometimes left in transp
and prim^unglue
terms. This was not the case if I used a particular concrete type for A, or if I used a similar construction using the equivalence.
Example:
...ANSWER
Answered 2021-Apr-08 at 06:41In the agda/cubical
library we do tend to export the equivalence (or the iso) along with the path, because of issues like the one you mention.
The reason for those extra transp
calls is that transport for Glue
has to work in the general case where they might actually be required.
fst (prim^unglue a)
should reduce away if you ask for the normal form though.
QUESTION
I'm trying to create an instance for bind operator (>>=)
to the custom type ST a
I found this way to do it but I don't like that hardcoded 0.
Is there any way to implement it without having the hardcoded 0 and respecting the type of the function?
...ANSWER
Answered 2021-Apr-07 at 01:27The most important thing to keep in mind is that your ST
type is a wrapper around a function. What if you started your definition as (>>=) = \s -> \f -> S (\n -> ... )
? It might be (ok, is) a bit silly to write separate lambdas for the s
and f
parameters there, but I did it to show that they're not really any different from the n
parameter. You can use it in your definition of (>>=)
.
QUESTION
I'm new to haskell and I dont know why I'm getting an extra element in a list.
Here's my code:
...ANSWER
Answered 2021-Mar-31 at 03:53You are defining two different list'
. The one inside the list comprehension list'<- (zip [0..] list)
shadows the previous one. Shadowing means you have two equal names in scope but the one lexically closer is the only one visible. You want something like:
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