Lists.Rmd

---
title: "Lists"
output: html_notebook
---
# August 3, 2021
Data Science and Machine Learning with R from A-Z Course [Updated for 2021]
# https://learning.oreilly.com/videos/data-science-and/9781801075282/9781801075282-video3_10/

This is an [R Markdown](http://rmarkdown.rstudio.com) Notebook. When you execute code within the notebook, the results appear beneath the code. 

Try executing this chunk by clicking the *Run* button within the chunk or by placing your cursor inside it and pressing *Cmd+Shift+Enter*. 

```{r}
list(1, "a", TRUE)
```
```{r}
x <- vector(mode = "list", length = 5)
```

Add a new chunk by clicking the *Insert Chunk* button on the toolbar or by pressing *Cmd+Option+I*.
```{r}
x <- list(1, "a", TRUE)
```

When you save the notebook, an HTML file containing the code and output will be saved alongside it (click the *Preview* button or press *Cmd+Shift+K* to preview the HTML file). 
```{r}
x[2]
```
```{r}
x[[2]]
```

The preview shows you a rendered HTML copy of the contents of the editor. Consequently, unlike *Knit*, *Preview* does not run any R code chunks. Instead, the output of the chunk when it was last run in the editor is displayed.

```{r}
lapply(x, class) -> types_x
index <- 2
x[[index]]
types_x[[index]]
```
```{r}
as.list(1:10)
```
```{r}
xlist <- list(a = "John Stevens", b = 1:10, data = head(iris))
```
```{r}
xlist[["data"]]
```
```{r}
data <- data.frame(Name = c("Athing", "Gabby", "Courtney"), Medal = c("Gold","Bronze","Silver"), Place = c(1, 3, 2))
data
```

```{r}
data[[2]]
```
```{r}
data[2]
```
```{r}
data[1:3]
```
```{r}
data[c(1,3)]
```


```{r}
sapply(chat, length)
```