---
title: "Venn Calculator"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{VennCalculator}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

```{r, include = FALSE}
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)
```

## How to use Venn Calculator?

`ggVennDiagram` has a series of set operation functions, and this can be used as the Venn calculator.

```{r setup}
library(ggVennDiagram)
set.seed(20231225)
y = list(
  A = sample(letters, 8) |> sort(),
  B = sample(letters, 8) |> sort(),
  C = sample(letters, 8) |> sort(),
  D = sample(letters, 8) |> sort())

y
```

First of all, we need to construct a `Venn` class object with this list. If you print this object, it will give meta information of the object.

```{r}
venn_y = Venn(y)

venn_y
```

* Find the overlapping members of two or more sets.

  ```{r}
  overlap(venn_y, 1:2) # members in both the first two sets
  overlap(venn_y) # members in all the sets
  ```

* Find the different members between sets and set unions

  ```{r}
  discern(venn_y, 1)  # members in set 1, but not in the resting sets
  discern(venn_y, c("A","B"), 3) # members in set A & B, but not in the 3rd set
  ```

* Find the specific members in one or more sets

  ```{r}
  discern_overlap(venn_y, 1)  # specific items in set 1
  discern_overlap(venn_y, 1:2)  # specific items in set 1 and set 2
  ```

* Find the union of two or more sets

  ```{r}
  unite(venn_y, 1:2) # union of set 1 and 2
  unite(venn_y, "all") # union of all four sets
  unite(venn_y, c("A", "B", "C"))
  ```

Combined results were provided as VennPlotData object.

  ```{r}
  pd = process_data(venn_y)
  pd
  ```

* `venn_set()`: get set data from the object. 

  ```{r}
  venn_set(pd)
  ```

* `venn_region()`: get subsets data from the object.

  ```{r}
  venn_region(pd)
  ```

Please note in order to keep the result concise, the containing items are nested. You may use the following methods to further process it.

* Method 1

  ```{r}
  venn_region(pd) |> tidyr::unnest(item)
  ```

* Method 2

  ```{r}
  venn_region(pd) |> dplyr::rowwise() |> dplyr::mutate(item = paste0(item, collapse = ", "))
  ```


## Reference

Some of these above-mentioned functions are originally developed by Turgut Yigit Akyol in `RVenn`.

*  Akyol T (2019). _RVenn: Set Operations for Many Sets_. R package version 1.1.0,
  <https://CRAN.R-project.org/package=RVenn>.