Changing Tick Intervals When X Axis Values Are Dates

Changing tick intervals when x axis values are dates

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You can change the x-axis labels using scale_x_date and formats from the scales package. Using the code from the ggplot2 scale_x_date help pages

library(ggplot2)
library(scales) # to access breaks/formatting functions
    
# Change Date to date format
aaci$dt <- as.Date(aaci$Date)

# Plot
# You can change the format to suit your requirements
ggplot(aaci, aes(x=dt, y=Average, colour=Species, group=Species)) +
      geom_point(size=4) +
      geom_line(size=1.3) + 
      scale_y_continuous(limits = c(0,100), breaks=seq(0,100,10)) + 
      scale_x_date(date_breaks = "months" , date_labels = "%b-%y")

Changing tick intervals when x-axis values are dates

# load our world in data covid data (https://github.com/owid/covid-19-data/tree/master/public/data/)
owid_data <- read.csv("owid-covid-data.csv")

# subset
df <- subset(owid_data, select=c(iso_code, location, date, total_cases_per_million, new_cases_per_million, new_cases_smoothed_per_million, total_deaths_per_million, new_deaths_per_million, new_deaths_smoothed_per_million, reproduction_rate, stringency_index, excess_mortality, excess_mortality_cumulative_per_million))
df <- subset(df, location == "Australia" | location == "Denmark" | location == "Germany"| location == "Netherlands" | location == "New Zealand"| location == "Sweden"| location == "Switzerland"| location == "United Kingdom")

# Convert "date variable" into class Date variable 
class(df$date)
df$date <- as.Date(df$date, "%Y-%m-%d")
class(df$date)

# Ggplot 
ggplot(df, aes(x=date, y=total_cases_per_million, group=location))+
  geom_line(aes(col=location), size=0.7)+
  theme_classic() + 
  theme(legend.title = element_text(face="bold"), plot.title = element_text(face="bold"), plot.caption = element_text(hjust = 0))+
  labs(col = "Country", 
       title = "Total confirmed cases of COVID-19 per million people",
       x = "Date",
       y = "COVID-19 cases per million people", 
       caption = "Source: COVID-19 Data Repository by the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University")+
  scale_y_continuous(breaks = seq(0,600000, by=100000), labels = scales::comma)+
  scale_x_date(limits = as.Date(c("2020-01-26","2022-05-16")), date_breaks = "1 month", date_minor_breaks = "1 day", date_labels = "%Y-%m-%d")```

MatPlotLib : Changing tick intervals when x axis values are dates

import matplotlib.dates as mdates

months = mdates.MonthLocator()  # every month
ax.xaxis.set_major_locator(months)

Try this

Controlling ggplot x-axis ticks that are dates

The scale_x_date(breaks=) argument can take a function, with which you can programmatically control the labels.

Edit: the use of "4" is hard-coded for my locale; I don't know what other locales may return for Wednesday, so it might be useful to replace 4 below with lubridate::wday("2020-05-20") (since today is Wednesday).

my_dates <- function(d) {
  seq( d[1] + (4 - wday(d[1])) %% 7, d[2] + 6, by = "week")
}

# ...
  scale_x_date(breaks = my_dates, date_labels = "%b %d") +
#...

Updated code (sans subtitle=, since we lack COVtests):

g <- stateWeekly %>% ggplot(aes(x = as.Date(weekStarting))) +
  geom_col(aes(y=100*dailyTest), size=0.75, color="darkblue", fill="white") +
  geom_line(aes(y=posRate), size = 0.75, color="red") +
  scale_y_continuous(name = "Test Positivity Rate", 
                     sec.axis = sec_axis(~./100, name="Percent of Pop Tested")) +
  scale_x_date(breaks = my_dates, date_labels = "%b %d") +
    labs(x = "Week Starting",
       title = "COVID-19 Testing",
       # subtitle = paste("Data as of", format(max(as.Date(COVtests$date)), "%A, %B %e, %y")),
       caption = "HQ AFMC/A9A \n Data: The COVID Tracking Project (https://covidtracking.com)") +
  theme(plot.title = element_text(size = rel(1), face = "bold"),
        plot.subtitle = element_text(size = rel(0.7)),
        plot.caption = element_text(size = rel(1)),
        axis.text.y = element_text(color='red'),
        axis.title.y = element_text(color="red"),
        axis.text.y.right = element_text(color="blue"),
        axis.title.y.right = element_text(color="blue"),
        axis.text.x = element_text(angle = 45,hjust = 1),
        strip.background =element_rect(fill="white"),
        strip.text = element_text(colour = 'blue')) +
  coord_cartesian(ylim=c(0,75)) +
  facet_wrap(~ state)

How to show date x-axis labels every 3 or 6 months in ggplot2

First convert date by: df$Month_Yr <- as.Date(as.yearmon(df$Month_Yr))

Then use this can solve the issue:

ggplot(reshaped_median, aes(x= Month_Yr, y = value))+ 
  geom_line(aes(color = Sentiments)) + 
  geom_point(aes(color = Sentiments)) + 
  #Here you set date_breaks  ="6 month" or what you wish
  scale_x_date(date_labels="%b-%d",date_breaks  ="3 month")+
  labs(title = 'Change in Sentiments (in median)', x = 'Month_Yr', y = 'Proportion of Sentiments %') + 
  theme(axis.text.x = element_text(angle = 60, hjust = 1))

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