ggplot2-分面(facet) 一页多图（转载）

本文更新地址:http://blog.csdn.net/tanzuozhev

本文在 http://www.cookbook-r.com/Graphs/Facets_(ggplot2)/的基础上加入了自己的理解

ggplot2的数据分面就是根据数据中的不同分组,绘制多个图形.

数据预览

library(reshape2)head(tips)

##   total_bill  tip    sex smoker day   time size## 1      16.99 1.01 Female     No Sun Dinner    2## 2      10.34 1.66   Male     No Sun Dinner    3## 3      21.01 3.50   Male     No Sun Dinner    3## 4      23.68 3.31   Male     No Sun Dinner    2## 5      24.59 3.61 Female     No Sun Dinner    4## 6      25.29 4.71   Male     No Sun Dinner    4

绘制散点图

library(ggplot2)sp <- ggplot(tips, aes(x=total_bill, y=tip/total_bill)) + geom_point(shape=1)sp

facet_grid

facet_grid() 可以根据数据的不同分组, 将图形按照 水平或者垂直方向 进行分割.共享x轴或者轴.

# 垂直方向进行分割sp + facet_grid(sex ~ .)

# 水平方向分割sp + facet_grid(. ~ sex)

# 对 sex 进行垂直分割, 对 day 进行水平分割sp + facet_grid(sex ~ day)

facet_wrap

facet_wrap()可以根据行列的数值进行分割

# 水平分割, 分为两列sp + facet_wrap( ~ day, ncol=2)

修改分页的标签外观

sp + facet_grid(sex ~ day) +    theme(strip.text.x = element_text(size=8, angle=75),          strip.text.y = element_text(size=12, face="bold"),          strip.background = element_rect(colour="red", fill="#CCCCFF"))

修改分页标签文字

labels <- c(Female = "Women", Male = "Men")sp + facet_grid(. ~ sex, labeller=labeller(sex = labels))

或者直接进行赋值

tips2 <- tipslevels(tips2$sex)[levels(tips2$sex)=="Female"] <- "Women"levels(tips2$sex)[levels(tips2$sex)=="Male"]   <- "Men"head(tips2, 3)

##   total_bill  tip   sex smoker day   time size## 1      16.99 1.01 Women     No Sun Dinner    2## 2      10.34 1.66   Men     No Sun Dinner    3## 3      21.01 3.50   Men     No Sun Dinner    3

# Both of these will give the same output:sp2 <- ggplot(tips2, aes(x=total_bill, y=tip/total_bill)) + geom_point(shape=1)sp2 + facet_grid(. ~ sex)

labeller

labeller() 通过输入一个方法, 对字符串进行该方法处理的,重新返回字符串.

# Reverse each strings in a character vectorreverse <- function(strings) {    strings <- strsplit(strings, "")    vapply(strings, function(x) {        paste(rev(x), collapse = "")    }, FUN.VALUE = character(1))}sp + facet_grid(. ~ sex, labeller=labeller(sex = reverse))

设置范围

一般情况下, 坐标轴的范围是固定的,也就是每幅图都有相同的尺寸和范围, 当然也可以设置free, free_x, 或者 free_y自由改变坐标轴的范围.

hp <- ggplot(tips, aes(x=total_bill)) + geom_histogram(binwidth=2,colour="white")# Histogram of total_bill, divided by sex and smokerhp + facet_grid(sex ~ smoker)

# scales="free_y", y轴自由设置hp + facet_grid(sex ~ smoker, scales="free_y")

# With panels that have the same scaling, but different range (and therefore different physical sizes)hp + facet_grid(sex ~ smoker, scales="free", space="free")

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