# [R] using text on the x axis ticks rather than numbers

Adaikalavan Ramasamy ramasamy at cancer.org.uk
Tue Sep 7 23:04:29 CEST 2004

```Out of curiosity, why is srt not respected in mtext ? See examples below

plot(1:10, xaxt="n");
par(srt=45)
mtext( paste("Point", LETTERS[1:10]), side=1, at=1:10 )

plot(1:10, xaxt="n");
mtext( paste("Point", LETTERS[1:10]), side=1, at=1:10, srt=45 )

It would be nice to have 'srt' as an argument in mtext in future.

On Tue, 2004-09-07 at 20:01, Marc Schwartz wrote:
> On Tue, 2004-09-07 at 12:52, Rajarshi Guha wrote:
> > Hello,
> >   is there a way in which I can use text labels rather than numbers on
> > the x axis ticks? I basically have a vector of (say) 8 points and I want
> > to plot these sequentially. Thus the x axis would have ticks at 1 .. 8.
> > Rather than having the labels 1 .. 8 I would like to have some arbitrary
> > text labels.
> >
> > Ideally I would like the labels to be rotated (say at 45 degrees) so
> > that they don't overlap with each other.
> >
> > Is this possible?
> >
> > Thanks,
>
>
> Here is an example. For the axis labels, you need to use text() and not
> mtext() as the latter does not allow for text rotation:
>
> # Set margins to make room for x axis labels
> par(mar = c(7, 4, 4, 2) + 0.1)
>
> # Create plot with no x axis and no x axis label
> plot(1:8, xaxt = "n",  xlab = "")
>
> # Set up x axis with tick marks alone
> axis(1, labels = FALSE)
>
> # Create arbitrary text
> labels <- paste("arbitrary text", 1:8, sep = " ")
>
> # plot x axis labels using:
> # par("usr")[3] - 0.25 as the vertical placement
> # srt = 45 as text rotation angle
> # adj = 1 to place right end of text at tick mark
> # xpd = TRUE to allow for text outside the plot region
> text(1:8, par("usr")[1] - 0.25, srt = 45, adj = 1,
>      labels = labels, xpd = TRUE)
>
> # plot x axis label at line 6 (of 7)
> mtext(1, text = "X Axis Label", line = 6)
>
>
> You can adjust the value of the '0.25' offset as required to move the x
> axis labels up or down relative to the x axis.
>
> HTH,
>
> Marc Schwartz
>
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