Why does the sorted dataframe rearrange when plotting?

Question

Originally the dataframe, df, was sorted I'm assuming as a string but was able to sort the alphanumeric vector:

df <- df[mixedorder(as.character(df$ID)),]

When creating a barplot the (x-axis) order changes back to 1 10a 10b 11 even though I explicitly changed the order to 1 2 3 4 5

Answer 1

library(tidyverse)

df <- data.frame(ID=(c("1", "2", "3", "4", "5", "10a", "10b", "11")), 
                 y=c(seq(100,500,100), 150, 155, 180), stringsAsFactors = FALSE)

Simple Fix for Simple Data

df$numId<-1:nrow(df)

ggplot(df, aes(x=reorder(ID,numId), y = y)) +
  geom_col() +
  labs(x='ID', y='Value')

Result

Create a function to make numberic value

create_id<-function(x) {
  if(!grepl('[a-z]',x,ignore.case = TRUE)) {
    return(as.numeric(x))
  } else {
    letter<-tolower(gsub('[0-9]+',"",x))
    letter_value<-which(letters==letter)/100
    number<-as.numeric(gsub('[a-z]',"",x)) + letter_value
    return(number)
  }
}

df<-df %>%
  group_by(ID, y) %>%
  mutate(nid = round(create_id(ID),3))

ggplot(df, aes(x=reorder(ID,nid), y = y)) +
  geom_col() +
  labs(x='ID', y='Value')

Result

Thank you to @user12728748 for the answer as well as providing the dataframe code. My answer is only here to satisfy the ggplot2 tag in the question. The answer above is just as suitable.