ggplot2 boxplots by week

Question

This code produces a single boxplot:

df <- data.frame(value = rnorm(62), my.date = seq(as.Date(\"2013-12-01\"), as.Date(\"2014-01-31\"), by=\"1 day\"))

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Answer 1

This fulfils @luciano's request to retain functionality of scale_x_date

library('scales')
library(ggplot2)
df <- data.frame(value = rnorm(62), my.date = seq(as.Date("2013-12-01"), as.Date("2014-01-31"), by="1 day"))
ggplot(df, aes(x=as.Date(my.date), y=value, group=format(as.Date(my.date),"%W-%b"))) + geom_boxplot() + scale_x_date(date_breaks = "1 week", date_labels="%Y-%b-%d")

Alternatively, if you don't want the data grouped by week# - which gives you the split around most new years - you can group by week ending Sundays as below. Adjusting from the Sunday weekending, to say Friday, can be achieved with some such code ceiling_date(x, "week") + ifelse(weekdays(x) %in% c("Saturday", "Sunday"), 5, -2)

ggplot(df, aes(x=as.Date(my.date), y=value, group=ceiling_date(my.date, "week"))) + geom_boxplot() + scale_x_date(date_breaks = "1 week", date_labels="%Y-%b-%d")

Answer 2

One option is to transform your date before using ggplot

library(ggplot2)
df <- data.frame(value = rnorm(62), 
my.date = seq(as.Date("2013-12-01"), as.Date("2014-01-31"), by="1 day"))
weeks <- format(df$my.date, "%Y/%W")
weeks <- factor(weeks, levels = unique(weeks))

ggplot(df, aes(weeks, value)) +
    geom_boxplot()

Answer 3

library(ggplot2)    
ggplot(df, aes(format(as.Date(my.date), "%W\n%b"), value)) + geom_boxplot()  

Edit:

To order the dates:

ggplot(df, aes(reorder(format(as.Date(my.date), "%W\n%b"), 
                       as.Date(my.date)), 
               value)) + 
  geom_boxplot()