CODEWITHSUNDEEP
rplot
Anusha
Anusha

Reputation: 1726

Defining Axis function in R

When drawing axis for time series, we usually create the tick marks and add the axis separately. Since I have to plot many time series, I tried to write the following function :

Simple plot command

 set.seed(1)

 x <- as.ts(rnorm(1:150))

 plot <- plot(x, xaxt = "n", yaxt = "n")

Convert a set of commands from this answer into a function

tt = seq(as.Date("1994-03-01"), by="months", length=150)

tsAxis <- function (tt) {

  ix <- seq_along(tt) # number of ticks 

  fmt <- "%b-%y"  # format of time 

  labs <- format(tt, fmt) # names or labels of dates

  axis(1, at = tt[ix], labels = labs[ix], 
       tcl = -0.7, cex.axis = 0.7, las = 2)
}

Then tsAxis(tt) must draw the axis but it doesnot and there is no error either. Even typing the commands separately does not plot the axis.

Any solutions?

Upvotes: 1

Views: 843

Answers (1)

ialm
ialm

Reputation: 8717

It seems that R represents the x-axis with integers in this case (i.e. x=1 is the first event, x=2 is the second event, etc.). You can see this if you run the code:

set.seed(1)
x <- as.ts(rnorm(1:150))
# Take a look at the x-axis
plot <- plot(x)

We can modify your code to reflect this:

tt = seq(as.Date("1994-03-01"), by="months", length=150)
tsAxis <- function (tt) {
  ix <- seq_along(tt) # number of ticks 
  fmt <- "%b-%y"  # format of time 
  labs <- format(tt, fmt) # names or labels of dates
  # Change "at=tt[ix]" to "at=ix" here!
  axis(1, at = ix, labels = labs[ix], 
       tcl = -0.7, cex.axis = 0.7, las = 2)
}

Or if you want to plot every third tick mark, just change ix <- seq_along(tt) to ix <- seq(1, length(tt), 3) and it should work.

Upvotes: 1

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