# [Rd] Re: [R] expressions in legends (PR#1302)

**ligges@statistik.uni-dortmund.de
**
ligges@statistik.uni-dortmund.de

*Thu, 7 Feb 2002 19:15:14 +0100 (MET)*

Robert Cunningham wrote:
>*
*>* Dear R-users,
*>*
*>* A few days ago I met the problem of using text produced with
*>* expression() in legend() being elevated relative to text produced
*>* without the expression() so that the alignment with pch and lty is
*>* also messed up. After ferreting through the help I finally came across
*>* an answer, the adj argument of legend(). You can see and example of
*>* this in the Math expressions example section of ?legends. Of course,
*>* many users would, I am sure, overlook this option and 'put up' with
*>* the mis-aligned legend. I wonder why expression() causes this problem
*>* and whether anything can be done about it (other that the adj hack).
*>*
*>* For those unaware of the problem paste this example into your R.
*>*
*>* plot(1:10,1:10)
*>* legend(1,10,"Non expression_species",pch=21,lty=1,bty='n')
*>* legend(5,10,expression(italic("Expression species")),pch=21,lty=1,bty='n',col=2)
*>* legend(8.1,10,expression(italic("E. species")),pch=21,lty=1,bty='n',col=2,adj=c(0,0.6))
*>*
*>* The first legend key is ordinary text, the second expression(italic())
*>* with no adjustment, the third with the adjustment.
*
This looks like a bug, so moved to r-bugs.
Let's simplify your example:
plot(1:10)
text(5, 10, "No expression ", adj=1)
text(5, 10, expression(" expression"), adj=0)
So the bug is in text(), not in legend.
I'll try to investigate the problem later this day / week.
Uwe Ligges
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