library(ggplot2)
#数据集
mtcars
#基本格式：ggplot(data,aes(x,y))+geom_xx()+annotate()+labs()
#aes是美化的意思，geom几何，annotate是注释，lab是标签
#散点图
ggplot(mtcars,aes(mpg,wt))+geom_point()
#线图
ggplot(mtcars,aes(mpg,wt))+geom_line()
#点线图
ggplot(mtcars,aes(mpg,wt))+geom_line()+geom_point()
#柱状图，是连续变量，变成因子
ggplot(mtcars,aes(cyl))+geom_bar()
class(mtcars$cyl)#类型
table(mtcars$cyl)#频次
#转换成因子，分类变量
ggplot(mtcars,aes(factor(cyl)))+geom_bar()
#分组，内部再分组（用am分类）,形成堆积柱形图
ggplot(mtcars,aes(factor(cyl),fill=factor(am)))+geom_bar()
#百分比的堆积柱形图
ggplot(mtcars,aes(factor(cyl),fill=factor(am)))+geom_bar(position="fill")
#如果不想堆积再加,并排
ggplot(mtcars,aes(factor(cyl),fill=factor(am)))+geom_bar(position = "dodge")
#直方图,一组数据
ggplot(mtcars,aes(mpg))+geom_histogram()
#密度图
ggplot(mtcars,aes(mpg))+geom_density()
#分类,color是对点线的描绘，fill是填充
ggplot(mtcars,aes((mpg),fill=factor(vs)))+geom_density()#全是密集填充
ggplot(mtcars,aes((mpg),fill=factor(vs)))+geom_density(alpha=0.5)#透明度为0.5
ggplot(mtcars,aes((mpg),col=factor(vs)))+geom_density()#col是点线图
#箱线图（最小值，最大值，中位数，上下四分位数）
ggplot(mtcars,aes(factor(vs),mpg))+geom_boxplot()
##分组作图,qsec是连续型变量为参考指标，vs是二分变量
ggplot(mtcars,aes(wt,mpg,color=qsec))+geom_point()
ggplot(mtcars,aes(wt,mpg,color=factor(vs)))+geom_point()
#aes内与外的区别
ggplot(mtcars,aes(wt,mpg))+geom_point()
ggplot(mtcars,aes(wt,mpg))+geom_point(color="blue")
ggplot(mtcars,aes(wt,mpg,color="yellow"))+geom_point()#会将color当成一个分组变量而不是颜色
#分面作图 facet_grid()
#1.轴刻度一致
#单变量作图
ggplot(mtcars,aes(wt,mpg))+geom_point()+facet_grid(.~vs)#不能有逗号,是句号,按照横轴排列
ggplot(mtcars,aes(wt,mpg))+geom_point()+facet_grid(vs~.)#是句号，纵轴排列
#双变量作图
ggplot(mtcars,aes(wt,mpg))+geom_point()+facet_grid(am~vs)
#不同的纵轴刻度
ggplot(mtcars,aes(wt,mpg))+geom_point()+facet_grid(vs~.,scale="free")
#调整图形,大小与形状
ggplot(mtcars,aes(wt,mpg,color=factor(vs)))+geom_point(shape=3,size=3)
#文本注释#标题#添加竖横线#"加号"，不能再第一行#互换XY
ggplot(mtcars,aes(wt,mpg,color=factor(vs)))+
geom_point(shape=3,size=3)+
annotate("text",x=4,y=20,label="yes")+
labs(title="hello",x="sss",y="yyy")+
geom_vline(xintercept = 3.5)+
geom_hline(yintercept = 20)+
coord_flip()
#调整刻度范围#替换刻度值
ggplot(mtcars,aes(wt,mpg,color=factor(vs)))+
geom_point(shape=3,size=3)+
annotate("text",x=4,y=20,label="yes")+
labs(title="hello",x="sss",y="yyy")+
geom_vline(xintercept = 4)+
geom_hline(yintercept = 2)+
xlim(3,8)+
ylim(15,25)+
scale_x_continuous(breaks=c(3,3.75),labels = c("a","b"))