Change x axis labels to hours (time) on geom_tile() - r

Question

Here is a geom_tile displaying hours and days of the week, how can it made to display each hour (i.e. 00:00 through to 23:00 on the x axis)?
library(tidyverse)
df %>%
ggplot(aes(hour, day, fill = value)) +
geom_tile(colour = "ivory")
Currently it displays every fifth hour:
I have tried a bunch of different things, and would prefer a 'best practice' way (i.e. without manually generating labels), but in case labels are needed, here's one way to produce them hour_labs <- 0:23 %>% { ifelse(nchar(.) == 1, paste0("0", .), .) } %>% paste0(., ":00")
Data for reproducible example
df <- structure(list(day = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L,
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 3L, 3L,
3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L,
4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 5L, 5L,
5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L,
5L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L,
6L, 6L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 7L), .Label = c("Sunday",
"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"
), class = c("ordered", "factor")), hour = c(0L, 2L, 3L, 5L,
6L, 7L, 8L, 10L, 11L, 12L, 13L, 18L, 21L, 22L, 23L, 0L, 1L, 2L,
3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L, 12L, 13L, 20L, 21L, 22L,
23L, 0L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L, 12L, 13L,
20L, 21L, 22L, 23L, 0L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L,
11L, 13L, 14L, 20L, 21L, 22L, 23L, 0L, 1L, 2L, 3L, 4L, 5L, 6L,
7L, 8L, 9L, 10L, 11L, 12L, 13L, 15L, 20L, 21L, 22L, 23L, 0L,
1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 11L, 13L, 14L, 15L, 16L,
19L, 21L, 0L, 1L, 2L, 3L, 7L, 8L, 10L, 13L, 14L, 22L, 23L), value = c(1L,
1L, 1L, 2L, 1L, 3L, 1L, 1L, 2L, 1L, 3L, 1L, 2L, 13L, 13L, 24L,
39L, 21L, 17L, 25L, 22L, 27L, 28L, 19L, 6L, 2L, 2L, 1L, 2L, 2L,
7L, 23L, 38L, 18L, 26L, 21L, 20L, 31L, 40L, 35L, 22L, 5L, 3L,
2L, 7L, 4L, 3L, 3L, 3L, 17L, 13L, 23L, 24L, 19L, 31L, 13L, 35L,
50L, 22L, 13L, 7L, 2L, 1L, 1L, 1L, 1L, 3L, 14L, 17L, 33L, 32L,
32L, 25L, 29L, 27L, 38L, 26L, 11L, 8L, 4L, 5L, 5L, 3L, 1L, 1L,
3L, 14L, 21L, 24L, 22L, 25L, 26L, 23L, 58L, 36L, 26L, 6L, 3L,
1L, 5L, 3L, 1L, 1L, 3L, 1L, 2L, 2L, 1L, 1L, 1L, 2L, 1L, 1L, 2L,
1L, 1L)), row.names = c(NA, -116L), groups = structure(list(day = structure(1:7, .Label = c("Sunday",
"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"
), class = c("ordered", "factor")), .rows = structure(list(1:15,
16:33, 34:51, 52:69, 70:88, 89:105, 106:116), ptype = integer(0), class = c("vctrs_list_of",
"vctrs_vctr"))), row.names = c(NA, 7L), class = c("tbl_df", "tbl",
"data.frame"), .drop = TRUE), class = c("grouped_df", "tbl_df",
"tbl", "data.frame"))

Answer 1

Here's one way using sprintf to construct labels.
library(dplyr)
library(ggplot2)
df %>%
mutate(lab = sprintf('%02d:00', hour)) %>%
ggplot() + aes(lab, day, fill = value) +
geom_tile(colour = "ivory") +
theme(axis.text.x = element_text(angle = 90, hjust = 1))
To complete the missing times apart from #Eric Watt's suggestion we can also use complete.
df %>%
mutate(lab = sprintf('%02d:00', hour)) %>%
tidyr::complete(lab = sprintf('%02d:00', 0:23)) %>%
ggplot() + aes(lab, day, fill = value) +
geom_tile(colour = "ivory") +
theme(axis.text.x = element_text(angle = 90, hjust = 1))

Answer 2

I would suggest making sure your data type is correctly representing your data. If your hour column is representing time in hours, then it should be a time based structure. For example:
df$hour <- as.POSIXct(as.character(df$hour), format = "%H", tz = "UTC")
Then you can tell ggplot that the x axis is a datetime variable using scale_x_datetime.
ggplot(df, aes(hour, day, fill = value)) +
geom_tile(colour = "ivory") +
scale_x_datetime(labels = date_format("%H:%M")) +
theme(axis.text.x = element_text(angle = 90, hjust = 1, vjust = 0.5))
If you want a break for every hour, you can input that as breaks:
ggplot(df, aes(hour, day, fill = value)) +
geom_tile(colour = "ivory") +
scale_x_datetime(breaks = as.POSIXct(as.character(0:23), format = "%H", tz = "UTC"),
labels = date_format("%H:%M")) +
theme(axis.text.x = element_text(angle = 90, hjust = 1, vjust = 0.5))
You can also use the scales package which has handy formatting options such as date_breaks:
library(scales)
ggplot(df, aes(hour, day, fill = value)) +
geom_tile(colour = "ivory") +
scale_x_datetime(breaks = date_breaks("1 hour"),
labels = date_format("%H:%M")) +
theme(axis.text.x = element_text(angle = 90, hjust = 1, vjust = 0.5))