ggplot 中多种因素的颜色和分面

Question

我有一个 data.frame，我试图以 facetted 的方式与 R 的 ggplot 的 geom_boxplot 一起绘制：

set.seed(1)

vals <- rnorm(12)
min.vals <- vals-0.5
low.vals <- vals-0.25
max.vals <- vals+0.5
high.vals <- vals+0.25


df <- data.frame(sample=c("c0.A_1","c0.A_2","c1.A_1","c1.A_2","c2.A_1","c2.A_2","c0.B_1","c0.B_2","c1.B_1","c1.B_2","c2.B_1","c2.B_2"),
                 replicate=rep(c(1,2),6),val=vals,min.val=min.vals,low.val=low.vals,max.val=max.vals,high.val=high.vals,
                 group=c(rep("A",6),rep("B",6)),cycle=rep(c("c0","c0","c1","c1","c2","c2"),2),
                 stringsAsFactors = F)

在这个例子中有两个因素我想要 facet:

facet.factors <- c("group","cycle")
for(f in 1:length(facet.factors)) df[,facet.factors[f]] <- factor(df[,facet.factors[f]],levels=unique(df[,facet.factors[f]]))
levels.vec <- sapply(facet.factors,function(f) length(levels(df[,f])))

但在其他情况下我可能只有一个或两个以上的因素。

有没有办法向 facet_wrap 传递分面的因子向量和列数？

这是我尝试过的方法，此外我还为每个因子级别创建了自己的颜色：

library(RColorBrewer,quietly=T)
library(scales,quietly=T)
level.colors <- brewer.pal(sum(levels.vec),"Set2")

require(ggplot2)
ggplot(df,aes_string(x="replicate",ymin="min.val",lower="low.val",middle="val",upper="high.val",ymax="max.val",col=facet.factors,fill=facet.factors))+
  geom_boxplot(position=position_dodge(width=0),alpha=0.5,stat="identity")+
  facet_wrap(~facet.factors,ncol=max(levels.vec))+
  labs(x="Replicate",y="Val")+
  scale_x_continuous(breaks=unique(df$replicate))+
  scale_color_manual(values=level.colors,labels=unname(unlist(sapply(facet.factors,function(f) levels(df[,f])))),name="factor level")+scale_fill_manual(values=level.colors,labels=unname(unlist(sapply(facet.factors,function(f) levels(df[,f])))),name="factor level")+
  theme_bw()+theme(legend.position="none",panel.border=element_blank(),strip.background=element_blank(),axis.title=element_text(size=8))

这显然会引发此错误：

Error in combine_vars(data, params$plot_env, vars, drop = params$drop) : 
  At least one layer must contain all variables used for facetting

显然这有效：

ggplot(df,aes_string(x="replicate",ymin="min.val",lower="low.val",middle="val",upper="high.val",ymax="max.val",col=facet.factors,fill=facet.factors))+
  geom_boxplot(position=position_dodge(width=0),alpha=0.5,stat="identity")+
  facet_wrap(group~cycle,ncol=max(levels.vec))+
  labs(x="Replicate",y="Val")+
  scale_x_continuous(breaks=unique(df$replicate))+
  scale_color_manual(values=level.colors,labels=unname(unlist(sapply(facet.factors,function(f) levels(df[,f])))),name="factor level")+scale_fill_manual(values=level.colors,labels=unname(unlist(sapply(facet.factors,function(f) levels(df[,f])))),name="factor level")+
  theme_bw()+theme(legend.position="none",panel.border=element_blank(),strip.background=element_blank(),axis.title=element_text(size=8))

但它忽略了我传递的颜色并且不添加图例，我想因为我无法将 vector 传递给 col 和 fill in [=26] =]，显然我必须对分面进行硬编码。

这对分面问题也不起作用：

ggplot(df,aes_string(x="replicate",ymin="min.val",lower="low.val",middle="val",upper="high.val",ymax="max.val",col=facet.factors,fill=facet.factors))+
      geom_boxplot(position=position_dodge(width=0),alpha=0.5,stat="identity")+
      facet_wrap(facet.factors[1]~facet.factors[2],ncol=max(levels.vec))+
      labs(x="Replicate",y="Val")+
      scale_x_continuous(breaks=unique(df$replicate))+
      scale_color_manual(values=level.colors,labels=unname(unlist(sapply(facet.factors,function(f) levels(df[,f])))),name="factor level")+scale_fill_manual(values=level.colors,labels=unname(unlist(sapply(facet.factors,function(f) levels(df[,f])))),name="factor level")+
      theme_bw()+theme(legend.position="none",panel.border=element_blank(),strip.background=element_blank(),axis.title=element_text(size=8))

所以我的问题是： 1.有没有办法将向量传递给facet_wrap？ 2. 有没有办法用因子向量而不是单个因子来着色和填充？

Answer 1

我们不能为单个框指定 coloring/filling 的两种颜色，我建议将分面变量粘贴在一起作为 coloring/filling 比例：

df$col.fill <- Reduce(paste, df[facet.factors])

facets of facet_wrap 接受字符向量或单边公式：

facet.formula <- as.formula(paste('~', paste(facet.factors,  collapse = '+')))

所以代码最终看起来像这样：

ggplot(df,
       aes_string(
           x = "replicate", ymin = "min.val", ymax = "max.val",
           lower = "low.val", middle = "val", upper = "high.val",
           col = "col.fill", fill = "col.fill"
       )) +
    geom_boxplot(position = position_dodge(width = 0),
                 alpha = 0.5,
                 stat = "identity") +
    facet_wrap(facet.factors, ncol = max(levels.vec)) +
    # alternatively: facet_wrap(facet.formula, ncol = max(levels.vec)) +
    labs(x = "Replicate", y = "Val") +
    scale_x_continuous(breaks = unique(df$replicate)) +
    theme_bw() +
    theme(
        #legend.position = "none",
        panel.border = element_blank(),
        strip.background = element_blank(),
        axis.title = element_text(size = 8)
    )

图例未显示，因为您添加了 legend.position = "none",。

顺便说一句，如果您在代码中添加一些 space 和换行符，肯定会提高可读性。

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