R语言ggplot2 title设置教程(main,axis和legend titles)

我是大南瓜 2023-03-20 我要评论

1. ggplot2中添加title函数

ggtitle(label) # for the main title，主题目
xlab(label) # for the x axis label， xlab
ylab(label) # for the y axis label， ylab
labs(...) # for the main title, axis labels and legend titles，可以同时设定多个lab和tittle

2. 实际应用

（1）添加title、xlab和ylab

ToothGrowth$dose <- as.factor(ToothGrowth$dose)
library(ggplot2)
p <- ggplot(ToothGrowth, aes(x=dose, y=len)) + geom_boxplot()
## 方法1：
p + ggtitle("Plot of length \n by dose") +
  xlab("Dose (mg)") + ylab("Teeth length")

## 方法2：
p +labs(title="Plot of length \n by dose",
        x ="Dose (mg)", y = "Teeth length")

（2）修改legend名字

# Default plot
p <- ggplot(ToothGrowth, aes(x=dose, y=len, fill=dose))+
  geom_boxplot()
p
# Modify legend titles
p + labs(fill = "Dose (mg)")

（3）修改title的字体，位置，颜色等

参数，其中hjust和vjust可以调节位置， anglexlab和ylab调节角度，size可以调节label大小：

family : font family
face : font face. Possible values are “plain”, “italic”, “bold” and “bold.italic”
colour : text color
size : text size in pts
hjust : horizontal justification (in [0, 1])
vjust : vertical justification (in [0, 1])
lineheight : line height. In multi-line text, the lineheight argument is used to change the spacing between lines.
color : an alias for colour
angle: angle

使用：

# Default plot
p <- ggplot(ToothGrowth, aes(x=dose, y=len)) + geom_boxplot() +
  ggtitle("Plot of length \n by dose") +
  xlab("Dose (mg)") + ylab("Teeth length")
p
# Change the color, the size and the face of
# the main title, x and y axis labels
p + theme(
plot.title = element_text(color="red", size=14, face="bold.italic"),
axis.title.x = element_text(color="blue", size=14, face="bold"),
axis.title.y = element_text(color="#993333", size=14, face="bold")
)

此外，修改坐标轴的angle也是相似的构造：

require(ggplot2)
ggplot(data=mtcars, aes(x=mpg, y=wt)) + geom_point()  + theme(axis.text.x = element_text(angle=90))
ggplot(data=mtcars, aes(x=mpg, y=wt)) + geom_point()  + theme(axis.text.y = element_text(angle=90))

（4）删除xlab和ylab

# Hide the main title and axis titles
p + theme(
  plot.title = element_blank(),
  axis.title.x = element_blank(),
  axis.title.y = element_blank())

总之，一次性设定ggplot相关title的话， labs(title=" ", x=" ",y=" ")即可，修改需要使用后面的theme(axis.text.x = element_text(angle=90))，类似这种设定。