How to show year in a date label only when it's a new year

Question

I'm plotting a time series graph across multiple years. I'd like each tick on the x-axis to indicate the year and month. But, I only want the year to appear sometimes

• When it's the earliest date of that year on the graph, the date should be "%Y-%b"
• When it's any other date that year, the format should be "%b"

Here's some example data

# Setup 
library(tidyverse)
library(patchwork)

# Set seed 
set.seed(123)

# Generate data
df_test <- 
  tibble(
    date = seq(as.Date("2010-1-1"), as.Date("2012-1-1"), by = "months"),
    value = rnorm(n = length(date), mean = 10, sd = 1))

And here's the graph atm

gg_full <- 
  df_test %>% 
  ggplot(
    aes(
      x = date, 
      y = value)) +
  geom_line() + 
  scale_x_date(
    date_breaks = "1 month",
    date_labels = "%b") + 
  theme(
    axis.text.x = element_text(angle = 45, hjust = 1))

gg_full

I'd like it to look something like this

If it's easier to plot the year labels separately beneath the month labels, that's also fine. I just want to indicate what year each month is in without having to include the year inside each and every month label.

Answer 1

Use scales::label_date_short:

df_test %>% 
  ggplot(aes(x = date, y = value)) +
  geom_line() + 
  scale_x_date(date_breaks = "1 month",
               labels = scales::label_date_short()) + 
  theme(axis.text.x = element_text(angle = 0, hjust = 1))