lesson 2a.Rmd

---
title: "Lesson 2a"
author: "[Ang Zhang](https://az.azhang.eu.org)"
output: 
  html_document:
    toc: true
    toc_float: true
    keep_md: true
date: "2024-08-23"

---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

## R Markdown

This is an R Markdown document. Markdown is a simple formatting syntax for authoring HTML, PDF, and MS Word documents. For more details on using R Markdown see <http://rmarkdown.rstudio.com>.

When you click the **Knit** button a document will be generated that includes both content as well as the output of any embedded R code chunks within the document. You can embed an R code chunk like this:

```{r cars}
summary(cars)
```

```{r}
head(iris)
```

```{r echo = FALSE}
x <- rnorm(100)
y <- 2 * x + rnorm(100)
cor(x, y)
```

```{r results = 'hide'}
x <- rnorm(100)
y <- 2 * x + rnorm(100)
cor(x, y)
```

```{r eval = FALSE}
x <- rnorm(100)
y <- 2 * x + rnorm(100)
cor(x, y)
```

```{r include = FALSE}
x <- rnorm(100)
y <- 2 * x + rnorm(100)
cor(x, y)
```

```{r, warning = FALSE, message=FALSE}
x <- rnorm(100)
y <- 2 * x + rnorm(100)
cor(x, y)
```

```{r, collapse=TRUE}
head(iris)
```

```{r, fig.align='center', fig.height=3, fig.width=4}
library(ggplot2)

ggplot(iris, aes(Sepal.Length, Sepal.Width, color = Species)) +
        geom_point()
```
## Including Plots

This is an example of in-line code: <u>**`r round(mean(mtcars$mpg), 1)`**</u>

```{r, results='asis'}
knitr::kable(iris)
```

```{r}
knitr::kable(head(iris), caption = 'Example caption for the iris data frame')
```

You can also embed plots, for example:

```{r pressure, echo=FALSE}
plot(pressure)
```

Note that the `echo = FALSE` parameter was added to the code chunk to prevent printing of the R code that generated the plot.