Support for data weights

[TonisOrmisson]

Describe the new feature
An option to use weight column for any calculations to use data weights.

I do not find the option in source code, but I found an existing question here:
https://stackoverflow.com/questions/71224873/how-to-use-weight-with-the-package-crsosstable-for-r

[TonisOrmisson]

I am very new to R, so I not in a position to make a PR for that yet, but in essence using weights would mean that instead of using counts of rows, sums of weight variable values of respective data rows should be used to get the "weighted" results.

[DanChaltiel]

Hi Tonis,

As of the current state, I'm not sure how to support weights in crosstable.

All variables are described using the funs argument which should be a list of summary functions (see the doc).
Summary functions as currently implemented take only one argument - the current column being described - and cannot access other columns.
In this context, I don't know how to pass the weight argument to any function, including for instance weighted.mean().

You can work this around by using a fixed reference to the weights, but it won't work with by=, as the length of the weight vector would become wrong.
Example:

library(tidyverse)
library(crosstable)

a = mtcars2 %>% 
  mutate(w = ifelse(am=="manual", 1, 2))

#works
a %>% 
  crosstable(where(is.numeric), 
             funs=c(mean=~mean(.x), weighted.mean = ~weighted.mean(.x, w=a$w)))

#doesn't work
a %>% 
  crosstable(where(is.numeric), by=vs, 
             funs=c(mean=~mean(.x), weighted.mean = ~weighted.mean(.x, w=a$w)))

If you (or anyone) have an idea of how I could implement this, I'd gladly add the feature.

EDIT

I understood your question as it was about numerical variables.

For categorical variables, you could use tidyr::uncount() to duplicate rows depending on a weighting variable:

a %>% 
  crosstable(am)
a %>% 
  uncount(w) %>% 
  crosstable(am)

Obviously, that will only work if your weighting variable is integer.
I have even less clue on how to implement that feature directly in crosstable, to be honest.

If you know of a package that does that, please let me know.

[TonisOrmisson]

Thanks for looking into it!

I am testing multiple crosstab packages to see the one more suitable, here is one that has weights implemented:

https://github.com/gdemin/expss

[DanChaltiel]

On GitHub, it's always a good idea to accompany a statement with code 😉
Please show a code that does what you want using expss. Using the reprex package is also highly recommended.

[TonisOrmisson]

I have not tried the expss with weights yet, its just what they state on their package page and what I noticed here, I have yet no Idea if this actually works, sry :)