R - ggplot2 issues with date as character for x-axis

Question

I'm new to using R and ggplot2, and I cannot figure out how to fix the issue with the graph I am trying to create.

Here is what the graph looks like at the moment. I have dates on the x-axis, but for some reason they don't work with the year, but only order by the month and day.

Here is a screenshot of the data I am working with:

As you can see, the order looks correct here.

I produced a re-creatable sample where the same issue occurs

Week <- c("1/6/2019", "1/26/2020", "6/7/2020")
Coronavirus <- c(0, 16, 67)
Grubhub <- c(65, 23, 59)
UberEats <- c(52, 80, 68)
Doordash <- c(27, 35, 50)

my.data <- data.frame(Week, Coronavirus, Grubhub, UberEats, Doordash)
my.data

test.output <- ggplot(data = my.data, aes(x = Week, group = 1)) +
  geom_line(aes(y = Coronavirus), color = "red") +
  geom_line(aes(y = Grubhub), color = "darkgreen") +
  geom_line(aes(y = UberEats), color = "blue") +
  geom_line(aes(y = Doordash), color = "purple") +
  theme(axis.text.x = element_text(angle = 90)) +
  labs(title = "Weekly Google Search Term Interest by Category", y = "Search Term Interest", x = "Week [2020]") 
test.output

The order of the dates on the x-axis are incorrect here as well.

Any suggestions on how I can fix the issue?

Keep searching on SO, and you'll find many questions that include "date on the x-axis" where the date is a character. To R, `"1/6/2019"` is not a date, and even if you try to order it, it will sort lexicographically, not date-wise. The resolution to this includes at a minimum converting your date variable to `Date` class, and if you need to further control the presentation on the x-axis (e.g., you really prefer `%m/%d/%Y` format), then look at `scale_x_date` and its formatting mechanisms. — r2evans, Mar 12 '21 at 19:51
Duplicates: [Convert character to Date in R](https://stackoverflow.com/questions/4310326/convert-character-to-date-in-r); [Formatting dates on X axis in ggplot2](https://stackoverflow.com/questions/11748384/formatting-dates-on-x-axis-in-ggplot2) — Henrik, Mar 12 '21 at 19:57

www · Answer 1 · 2021-03-12T19:57:02.493

2

You need to change your Week column to date format.

library(ggplot2)
library(lubridate)

my.data <- data.frame(Week, Coronavirus, Grubhub, UberEats, Doordash)
my.data$Week <- mdy(my.data$Week)

test.output <- ggplot(data = my.data, aes(x = Week, group = 1)) +
  geom_line(aes(y = Coronavirus), color = "red") +
  geom_line(aes(y = Grubhub), color = "darkgreen") +
  geom_line(aes(y = UberEats), color = "blue") +
  geom_line(aes(y = Doordash), color = "purple") +
  theme(axis.text.x = element_text(angle = 90)) +
  labs(title = "Weekly Google Search Term Interest by Category", y = "Search Term Interest", x = "Week [2020]") 
test.output

If you don't want to use the mdy function. The following will also work.

my.data$Week <- as.Date(my.data$Week, format = "%m/%d/%Y")

edited Mar 12 '21 at 19:57

answered Mar 12 '21 at 19:53

www

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is the lubridate package needed for this? – Pecker Mar 12 '21 at 19:54
`lubridate` is for the `mdy` function. – www Mar 12 '21 at 19:55
Please see my update. You can also use `as.Date` if you want. – www Mar 12 '21 at 19:57

score 2 · Accepted Answer · answered Mar 12 '21 at 19:55

"1/6/2019" is not a date, it is a string. ggplot2 (and most other things) should never infer that you want it dealt with as a date. What it does "know" is that it is a string, and since it is not a factor, it orders things lexicographically (not year-first). Note that this matches your observation that it sorts first by month, then day, since those are the first few characters in the strings.
Once we make the Week column a proper Date class, if you want to keep the presentation in the "%m/%d/%Y" format, you need to add scale_x_date.

Week <- c("1/6/2019", "1/26/2020", "6/7/2020")
Coronavirus <- c(0, 16, 67)
Grubhub <- c(65, 23, 59)
UberEats <- c(52, 80, 68)
Doordash <- c(27, 35, 50)

my.data <- data.frame(Week, Coronavirus, Grubhub, UberEats, Doordash)
my.data$Week <- as.Date(my.data$Week, format = "%m/%d/%Y")
my.data

test.output <- ggplot(data = my.data, aes(x = Week, group = 1)) +
  geom_line(aes(y = Coronavirus), color = "red") +
  geom_line(aes(y = Grubhub), color = "darkgreen") +
  geom_line(aes(y = UberEats), color = "blue") +
  geom_line(aes(y = Doordash), color = "purple") +
  theme(axis.text.x = element_text(angle = 90)) +
  labs(title = "Weekly Google Search Term Interest by Category", y = "Search Term Interest", x = "Week [2020]") 
test.output

If you prefer "%m/%d/%Y", then

test.output + scale_x_date(date_labels = "%m/%d/%Y")

R - ggplot2 issues with date as character for x-axis

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