如何使用一维数据框在ggplot aes中设置x，y？

Question

df <- data.frame(
    cola = c('1',NA,'c','1','1','e','1',NA,'c','d'),
    colb = c("A",NA,"C","D",'a','b','c','d','c','d'),
    colc = c('a',NA,'c','d','a',NA,'c',NA,'c','d'),stringsAsFactors = TRUE)

bad<-lapply(df, function(x) sum(is.na(x))/nrow(df))
bad<-as.data.frame(bad)

I want to make bar plot to one dimension dataframe bad .

X axis should be cola , colb , colc ,Y axis should be 0.2 , 0.1 , 0.3 . Then I tried but failed:

ggplot(bad,aes(x=colnames(bad), y=bad[1,])) + 
    geom_bar(stat='identity')

As to one dimension dataframe,how to set aes(x=?,y=?) ?

Answer 1

You need to convert your data frame to long format. You can use reshape2's melt function.

dab <- reshape2::melt(bad)

> dab
  variable value
1     cola   0.2
2     colb   0.1
3     colc   0.3

ggplot(dab) + geom_bar(aes(x=variable, y=value, fill=variable), stat='identity')

Answer 2

You need to change the dimension of the dataframe

library(ggplot2)
ggplot(stack(bad), aes(ind, values)) + geom_bar(stat='identity')

Or if you want to go the tidyverse way we can use gather as well

ggplot(tidyr::gather(bad), aes(key, value)) + geom_bar(stat='identity')