---
title: "Untitled"
author: "JIASHU MIAO"
date: "2/8/2019"
output: html_document
---

```{r}
df <- data.frame( x = 1:3,
y = c("a", "b", "c"),
stringsAsFactors = FALSE)
typeof(df)
df[[1]] 
df[1,]
df[1]
df[2]
df[[2]]
```

```{r}
sss <- list(c(TRUE, "A"),list(c(1:3),TRUE, "a"))
sss[1][1]
sss[[2]][[1]][1]
```
```{r}
x=c(TRUE,FALSE)
y=c(0,1,1,2)
y==x
```

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

```{r}




```


