webR-enabled code cells

Author

Roy Francis

Published

06-Sep-2024

1 Installation

Install webr extension for quarto by running:

quarto add coatless/quarto-webr

then add to yaml:

webr:
   channel-type: "post-message"
engine: knitr
filters:
  - webr

webR-enabled code cell are established by using {webr-r} in a Quarto HTML document.

2 Sample cases

2.1 Fit a linear regression model

2.2 Create a graph with base R

2.3 Packages

2.3.1 Available Packages

You can view what packages are available for webR by either executing the following R code (either with WebR or just R). This chunk is an R chunk that is not evaluated.

available.packages(
  repos = "https://repo.r-wasm.org/",
  type = "source"
)[, c("Package", "Version")]

Or, by navigating to the WebR repository:

https://github.com/r-wasm/webr-repo/blob/main/repo-packages

2.3.2 Installing a Package

Installing ggplot2 may take at least 2 minutes to run.

2.3.3 Using a Package

Once ggplot2 is loaded, then use the package as normal.

2.4 Define variables and re-use them in later cells

2.5 Escape characters in a string

2.6 Anonymous function definition

2.7 Empty code cell

2.8 Pre-rendered R code cell

message("Hello!")

Hello!

3 Session

webr extension version: 0.3.6

---
title: "webR-enabled code cells"
subtitle: Live R in quarto documents using web-r quarto extension
author: "Roy Francis"
date:  last-modified
date-format: "DD-MMM-YYYY"
format:
  html:
    fig-align: left
    title-block-banner: true
    toc: true
    number-sections: true
    code-tools: true
webr:
   channel-type: "post-message"
engine: knitr
filters:
  - webr
---

## Installation

Install webr extension for quarto by running:

```bash
quarto add coatless/quarto-webr
```

then add to yaml:

```yaml
webr:
   channel-type: "post-message"
engine: knitr
filters:
  - webr
```

webR-enabled code cell are established by using `{webr-r}` in a Quarto HTML document.

```{webr-r}
1 + 1
```

## Sample cases

### Fit a linear regression model

```{webr-r}
fit <- lm(mpg ~ am, data = mtcars)
summary(fit)
```

### Create a graph with base R

```{webr-r}
plot(pressure)
```

### Packages
#### Available Packages

You can view what packages are available for webR by either executing the following R code (either with WebR or just R). This chunk is an R chunk that is not evaluated.

```{r,eval=FALSE}
available.packages(
  repos = "https://repo.r-wasm.org/",
  type = "source"
)[, c("Package", "Version")]
```

Or, by navigating to the WebR repository:

<https://github.com/r-wasm/webr-repo/blob/main/repo-packages>

#### Installing a Package

Installing `ggplot2` may take at least 2 minutes to run. 

```{webr-r}
webr::install("ggplot2")
```

#### Using a Package

Once `ggplot2` is loaded, then use the package as normal.

```{webr-r}
library(ggplot2)

p <- ggplot(mpg, aes(class, hwy))
p + geom_boxplot()
```

### Define variables and re-use them in later cells

```{webr-r}
name <- "James"
age <- 42
```

```{webr-r}
message(name, " is ", age, " years old!")
```

### Escape characters in a string

```{webr-r}
seven_seas <- "Ahoy, matey!\nLet's set sail for adventure!\n"
seven_seas
```

### Anonymous function definition

```{webr-r}
add_one <- \(x) x + 1
add_one(2)
```

### Empty code cell

```{webr-r}

```

### Pre-rendered R code cell

```{r}
message("Hello!")
```

## Session

```{webr-r}
sessionInfo()
```

webr extension version: 0.3.6