Order x-axis numerically ggplot2-CodePudding

I have the following dataframe (df):

# A tibble: 6 × 2
  chromosome     n
  <chr>      <int>
1 TcChr34-S     16
2 TcChr41-S     10
3 TcChr28-S      9
4 TcChr11-S      2
5 TcChr2-S       1
6 TcChr5-S       1

I want to make a barplot using ggplot2:

ggplot(data = df, 
       aes(y=n, 
           x=chromosome))   
  geom_bar(stat = "identity")

However, the x-axis labels are not generated in numerical order. How can I fix it, i.e., put it in the following order?

"TcChr2-S", "TcChr5-S", "TcChr11-S", "TcChr28-S", "TcChr34-S", "TcChr41-S"

CodePudding user response：

To order in ascending order of the numbers of chromosome, we have to pick out the numbers out of the string. This could be done with readrs parse_number() function (by the way up to this time my favorite function). The whole process is wrapped into to ´forcats´ ´fct_reorder´ function:

library(tidyverse)
df %>%
  ggplot(aes(y=n, x=fct_reorder(chromosome, parse_number(chromosome))))   
  geom_bar(stat = "identity")