Module 05 · RStudio & GitHub

Creating Data Visualizations using ggplot使用 ggplot 创建数据可视化

In this lab, you will learn how to create some basic visualizations in R.

Objective for Exercise 练习目标

We will create different data visualizations using the ggplot package using the inbuilt dataset in R called mtcars
我们将使用 ggplot 包，基于 R 中的内置数据集 mtcars 创建不同的数据可视化。

Click on the + symbol on the top left and choose R Script from the menu to open a new R edit window in RStudio:
点击 RStudio 左上角的 + 符号，从菜单中选择 R Script ，以在 RStudio 中打开一个新的 R 编辑窗口：

Read and view the first 5 rows of the Data using the following:
使用以下方法读取并查看数据的前 5 行：
```
library(datasets)

#Load Data

data(mtcars)

#View first 5 rows

head(mtcars, 5)
```
Type this ?mtcars to get information about the variables. This will print the information at the bottom right panel, on the Help tab
输入这个 ?mtcars 获取关于变量的信息。这将把信息打印在右下角的面板中，在 Help 标签页
Copy and paste the following code to load the ggplot package and create a scatterplot of disp and mpg.
复制并粘贴以下代码以加载 ggplot 包并创建 disp 和 mpg 的散点图。
```
#load ggplot package
library(ggplot2)

#create a scatterplot of displacement (disp) and miles per gallon (mpg)

ggplot(aes(x=disp,y=mpg,),data=mtcars)+geom_point()
```

Use the following code to add a title.
使用以下代码添加标题。

#Add a title

ggplot(aes(x=disp,y=mpg,),data=mtcars)+geom_point()+ggtitle("displacement vs miles per gallon")

Use the following code to change the name of the x-axis and y-axis
使用以下代码更改 x-axis 和 y-axis 的名称。

#change axis name

ggplot(aes(x=disp,y=mpg,),data=mtcars)+geom_point()+ggtitle("displacement vs miles per gallon") + labs(x = "Displacement", y = "Miles per Gallon")

Use the following to create a boxplot of the the distribution of mpg for the individual Engine types vs Engine (0 = V-shaped, 1 = straight)
使用以下方法为不同的发动机类型 vs Engine (0 = V-shaped, 1 = straight) 创建 mpg 分布的箱线图：
To do this you have to make vs a string or factor.
为此，您必须将 vs 转换为字符串或因子。
```
#make vs a factor
mtcars$vs <- as.factor(mtcars$vs)

#create boxplot of the distribution for v-shaped and straight Engine

ggplot(aes(x=vs, y=mpg), data = mtcars) + geom_boxplot()
```

Add color to the boxplots to help differentiate:
为箱线图添加颜色以帮助区分：

ggplot(aes(x=vs, y=mpg, fill = vs), data = mtcars) +
  geom_boxplot(alpha=0.3) +
  theme(legend.position="none")

Finally, let us create the histogram of weight wt.
最后，让我们创建重量 wt 的直方图。
```
ggplot(aes(x=wt),data=mtcars) + geom_histogram(binwidth=0.5)
```

This concludes this lab, we hope that you had fun!
本次实验到此结束，希望您玩得开心！

Author(s) 作者

Aije Egwaikhide