ggplot2 geom_bar - 如何保持data.frame的顺序

Question

我对geom_bar中的数据顺序有疑问。

这是我的数据集：

  SM_P,Spotted melanosis on palm,16.2
  DM_P,Diffuse melanosis on palm,78.6
  SM_T,Spotted melanosis on trunk,57.3
  DM_T,Diffuse melanosis on trunk,20.6
  LEU_M,Leuco melanosis,17
  WB_M,Whole body melanosis,8.4
  SK_P,Spotted keratosis on palm,35.4
  DK_P,Diffuse keratosis on palm,23.5
  SK_S,Spotted keratosis on sole,66
  DK_S,Diffuse keratosis on sole,52.8
  CH_BRON,Dorsal keratosis,39
  LIV_EN,Chronic bronchities,6
  DOR,Liver enlargement,2.4
  CARCI,Carcinoma,1

我指定了以下姓氏：

  colnames(df) <- c("abbr", "derma", "prevalence") # Assign row and column names

然后我绘制：

  ggplot(data=df, aes(x=derma, y=prevalence)) + geom_bar(stat="identity") + coord_flip()

为什么ggplot2会随机更改数据的顺序。我希望我的数据顺序与我的data.frame一致。

非常感谢任何帮助！

Answer 1

发布答案，因为评论线程变长了。您必须使用用aes(x=...)

映射的变量的因子级别来指定顺序

# lock in factor level order
df$derma <- factor(df$derma, levels = df$derma)

# plot
ggplot(data=df, aes(x=derma, y=prevalence)) + 
    geom_bar(stat="identity") + coord_flip()

结果，与df中的订单相同：

# or, order by prevalence:
df$derma <- factor(df$derma, levels = df$derma[order(df$prevalence)])

相同的plot命令给出：

我读了这样的数据：

read.table(text=
"SM_P,Spotted melanosis on palm,16.2
DM_P,Diffuse melanosis on palm,78.6
SM_T,Spotted melanosis on trunk,57.3
DM_T,Diffuse melanosis on trunk,20.6
LEU_M,Leuco melanosis,17
WB_M,Whole body melanosis,8.4
SK_P,Spotted keratosis on palm,35.4
DK_P,Diffuse keratosis on palm,23.5
SK_S,Spotted keratosis on sole,66
DK_S,Diffuse keratosis on sole,52.8
CH_BRON,Dorsal keratosis,39
LIV_EN,Chronic bronchities,6
DOR,Liver enlargement,2.4
CARCI,Carcinoma,1", header=F, sep=',')
colnames(df) <- c("abbr", "derma", "prevalence") # Assign row and column names