Date format for subset of ticks on time axis

Question

Problem

I would like to format my X-axis (time) so that the weekends are clearly visible. I would like to display the date as well as the day of the wee

Answer 1

You can use your custom formater for labels also using breaks="1 day" argument, you just have to use function(x) after labels= and replace myDate$timestamp with x. This will also solve the third problem.

 + scale_x_date(breaks="1 day", 
      labels= function(x) paste(substr(format(x, "%a"),1,1),format(x, "%d"),sep="\n")) 

Or you can make your transformation as seperate function and then use it for labels=.

my_date_trans<-function(x) {
      paste(substr(format(x, "%a"),1,1),format(x, "%d"),sep="\n")
}

+ scale_x_date(breaks="1 day",labels=my_date_trans)

To change colors for labels you should use theme() and axis.text.x=. Here I using vector of colors that contains 6 time black and then red as your scale starts with Monday. Those colors are then repeated.

ggplot() +
      geom_rect(data=rects, aes(xmin=saturdays, xmax=sundays,ymin=-Inf, ymax=Inf), alpha=0.1) +
      geom_line(data=myData, aes(x=timestamp, y=value, colour=variable,size=1)) + 
      geom_point(data=myData, aes(x=timestamp, y=value, colour=variable,size=2)) +
      scale_x_date(breaks="1 day",labels=my_date_trans)+
      scale_size_continuous(range = c(1.5,5), guide=FALSE)+
      theme(axis.text.x=element_text(color=c(rep("black",6),"red")))