Unable to order x axes in R

[serpa.k]

Hi
I'm trying to do a simple histogram with the biomass of a specific insect over the course of a year. Despite the order of the data in my spreadsheet, R is putting the x-axis in alphabetical order.
I've searched for some solutions here but no solution so far.

Code and Plot below:

library(ggplot2)
library(forcats)
library(dplyr)

#x axis change test 2

# data
df <- data.frame(
  Month = Triplectides_biomass$Month,
  Biomass = Triplectides_biomass$Biomass,
  Area = Triplectides_biomass$Area
  )

# Mean and standard error
df_summary <- df %>%
  group_by(Month, Area) %>%
  summarise(
    Mean_Biomass = mean(Biomass),
    SE_Biomass = sd(Biomass) / sqrt(n())
  )

# Plot
ggplot(df_summary, aes(x = Month, y = Mean_Biomass, fill = Area)) +
  geom_bar(stat = "identity", position = position_dodge()) +
  geom_errorbar(
    aes(ymin = Mean_Biomass - 1.96 * SE_Biomass,
        ymax = Mean_Biomass + 1.96 * SE_Biomass),
    width = 0.2,
    position = position_dodge(width = 0.9)  # Center the error bars
  ) +
  labs(x = "Months", y = "Biomass (0.001g)", title = "Average Biomass of Triplectides") +
  theme_minimal()

Any suggestions?

[M_AcostaCH]

Hi @serpa.k , for get a better help try to put a reproducible example o the data, see this ways

FAQ: How to do a minimal reproducible example ( reprex ) for beginners

A minimal reproducible example consists of the following items: A minimal dataset, necessary to reproduce the issue The minimal runnable code necessary to reproduce the issue, which can be run on the given dataset, and including the necessary information on the used packages. Let's quickly go over each one of these with examples: Minimal Dataset (Sample Data) You need to provide a data frame that is small enough to be (reasonably) pasted on a post, but big enough to reproduce your issue. Let's say, as an example, that you are working with the iris data frame head(iris) #> Sepal.Length Sepal.Width Petal.Length Petal.Width Species #> 1 5.1 3.5 1.4 0.…

I see that you don't put the Month column like a Date form? So, ggplot2 use this axis like a factor and not like a date.

With lubridate you could make this
cheatsheets>lubridate

[mduvekot]

Well, first of all, that's not a histogram. But never mind that. To reorder the Months by some other value, you can use reorder, as in

ggplot(df_summary, aes(x = reorder(Month, Mean_Biomass, decreasing = TRUE), y = Mean_Biomass, fill = Area))

[serpa.k]

Hi @M_AcostaCH , thanks for the answer

A exemple of my data:

Tripl_Bio <-tibble::tribble(
       ~Month..Area..Biomass,
     "July22 Coffee  0,0103",
       "Oct  Coffee  0,0125",
  "Feb23  Coffee  0,00,0136",
   "July22 Preserved 0,0055",
    "Oct22 Preserved 0,0563",
   "Feb23  Preserved 0,0114"
  )

head(Tripl_Bio)
#> # A tibble: 5 × 1
#>   Month..Area..Biomass    
#>   <chr>                   
#> 1 July22 Coffee  0,0103   
#> 2 Oct  Coffee  0,0125     
#> 3 Feb23  Coffee  0,00,0136
#> 4 July22 Preserved 0,0055 
#> 5 Oct22 Preserved 0,0563
#> 6 Feb23  Preserved 0,0114

Created on 2024-03-20 with reprex v2.1.0

About ludridate I trying figure out how to use properly without do changes manually.

[serpa.k]

Hi @mduvekot , thanks for the reply

Using this I can reorder but still not in a chronologic order. I need the axel go from July2022 to June2023

[jrkrideau]

That tibble seems completely messed up. I think this data.frame is what was intended.

Tripl_Bio <- structure(list(Month = c("July 22", "Oct 01", "Feb 23", "July 22", 
"Oct 22", "Feb 23"), Area = c(" Coffee", " Coffee", " Coffee", 
" Preserved", " Preserved", " Preserved"), Biomas = c(0.0103, 
0.0125, 0.0136, 0.0055, 0.0563, 0.0114)), class = "data.frame", row.names = c(NA, 
-6L)) 

[mduvekot]

@serpa.k

       "Oct  Coffee  0,0125",
  "Feb23  Coffee  0,00,0136",
   "July22 Preserved 0,0055",
    "Oct22 Preserved 0,0563",
   "Feb23  Preserved 0,0114"

your dates are not data objects, they're text strings, so they can't be sorted chronologically. Convert them to dates, then use scale_x_date(). Something like this:

library(tidyverse)
tribble(
  ~Month, ~Year, ~Area, ~Biomass,
  "Jul", 2022, 'Coffee', 0.0103,
  "Oct", 2022,  "Coffee",  0.0125,
  "Feb", 2022,  "Coffee",  0.0136,
  "Jul", 2022, "Preserved", 0.0055,
  "Oct", 2022, "Preserved", 0.0563,
  "Feb", 2022,  "Preserved", 0.0114
) %>% 
  mutate(
    date = as.Date(paste0(Year, "-", Month, "-01"), format = "%Y-%b-%d")
    ) %>%
  ggplot(aes(x = date, y = Biomass, fill = Area)) +
  geom_col(position = position_dodge())+
  scale_x_date(date_labels = "%b\n%y", date_breaks = "1 month")

[dromano]

Hi Karoline,

I believe a small tweak to your df, similar @mduvekot's suggestion, from your original code should work. Here is the tweak along with the rest of your original code:

df <- data.frame(
  Month = Triplectides_biomass$Month,
  Biomass = Triplectides_biomass$Biomass,
  Area = Triplectides_biomass$Area
  ) |> 
  # add a 'date' column that expresses 'Month' as date
  # (the value "%b %y" captures your strings of the form "Apr 23")
  # (%b stands for "a[b]brevaition" and %y stands for two-digit [y]ear) 
  mutate(date = parse_date(Month, format = "%b %y")) |> 
  # use 'date' column to give "Month" column chronological order
  mutate(Month = fct_reorder(Month, date))

# Mean and standard error
df_summary <- df %>%
  group_by(Month, Area) %>%
  summarise(
    Mean_Biomass = mean(Biomass),
    SE_Biomass = sd(Biomass) / sqrt(n())
  )

# Plot
ggplot(df_summary, aes(x = Month, y = Mean_Biomass, fill = Area)) +
  geom_bar(stat = "identity", position = position_dodge()) +
  geom_errorbar(
    aes(ymin = Mean_Biomass - 1.96 * SE_Biomass,
        ymax = Mean_Biomass + 1.96 * SE_Biomass),
    width = 0.2,
    position = position_dodge(width = 0.9)  # Center the error bars
  ) +
  labs(x = "Months", y = "Biomass (0.001g)", title = "Average Biomass of Triplectides") +
  theme_minimal()