Giving Specific Breaks in ggplot-CodePudding

I have CSV data where I have two columns and I need to plot Time as x axis and count as y axis. The time in the data ranges from 2008 Sep to 2021 Dec. Data points are monthly.

This is my

I want to put 5 certain time points in the x axis like below:

This is what I tried:

library(ggplot2)
theme_set(
  theme_bw(),
  theme(legend.position = "top")
)

result <- read.csv("Downloads/Questions Trend - Questions Trend.csv")
p <- ggplot(result, aes(result$Time_Formatted, result$VCS_Feature_History_Sanitize_Trnd))   
     geom_point(size = 0.1)   xlab("Month")   ylab("Temporal Trend")
p   geom_smooth(method = "loess", color = "red")

I tried below and could remove some points but still can not customize to specific points.

library(ggplot2)
library(scales)
theme_set(
  theme_bw(),
  theme(legend.position = "top")
)

result <- read.csv("Downloads/Questions Trend - Questions Trend.csv")
result$Time_Formatted <- as.Date(result$Time_Formatted)
p <- ggplot(result, aes(result$Time_Formatted, result$VCS_Feature_History_Sanitize_Trnd))   
     geom_point(size = 0.1)   xlab("Month")   ylab("Temporal Trend")  
    scale_x_date(date_breaks = "years" , date_labels = "%b-%y")
p   geom_smooth(method = "loess", color = "red")

How to give specific points in the x axis?

CodePudding user response：

You should use the scale_x_date() function of the ggplot2 package.

For example, here a code I'm always using in my work when I need to plot time data :

ggplot2::scale_x_date(name   = " ",
                        breaks = function(date) seq.Date(from = lubridate::ymd("2020-01-01") 1, 
                                                         to = lubridate::today(), 
                                                         by = "1 month"),
                        limits = c(lubridate::ymd("2020-07-13"),
                                   lubridate::today()),
                        expand  = c(0,0),
                        labels = scales::date_format("%b %Y"))

With breaks, you can choose to only show the first date of each month.

With labels and the function date_format() from the scales package, you can choose the date format, and you can basically do anything you want. Here, I choose to plot the month in letters and the year in number.

CodePudding user response：

Most of your problems here are related to reading in the date data so that the format is correctly recognised - this can be done by specifying it explicitly:

result <- read.csv("Test.csv")
result$Time_Formatted <- as.Date(result$Time_Formatted, "%m/%d/%y")

Then it's simply a case of making a vector indicating where you want breaks and specifying this in the scale_x_date with:

date_breaks <- as.Date(c("1/7/10", "1/12/12", "1/1/14", "1/2/15", "1/3/16"), "%d/%m/%y")

p <- ggplot(result, aes(Time_Formatted, VCS_Feature_History_Sanitize_Trnd))   
      geom_point(size = 0.1)   xlab("Month")   ylab("Temporal Trend")  
      scale_x_date(breaks=date_breaks , date_labels = "%b-%y")
p   geom_smooth(method = "loess", color = "red")

Note that I've removed the explicit reference to "result" in the aes() function as that's unnecessary and depricated according to the warning it creates. The end result is: