how to display a string containing greek chrs and variables

I'm trying something that I thought would be pretty simple, but it's proving
quite frustrating...

I want to display, for instance, the correlation coefficient "rho" in a
graph.

I can do something like:

text(x, y, paste("rho =", cor))

where cor would be my previously calculated correlation coefficient, and x
and y the coordinates.
Obviously that displays "rho", not the greek letter rho.

I can do also this:

text(x, y, paste("\\*r =",cor), vfont = c("sans serif","bold"))

that works, but that doesn't look very "pretty".
What looks good is doing something like:

text(x, y, expression(rho))

But I haven't managed to make it do what I need.

I can get this:
text(x, y, expression(rho == 0.8))

that looks good, but how can I substitute the "0.8" for teh name of a
numeric variable whose value is 0.8?

I'm going slightly mad... it can't be that hard.

Thanks for any help!

Jose


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Dr. Jose I. de las Heras ? ? ? ? ? ? ? ? ? ? ?Email: J.delasHeras at ed.ac.uk
The Wellcome Trust Centre for Cell Biology ? ?Phone: +44 (0)131 6513374
Institute for Cell & Molecular Biology ? ? ? ?Fax: ? +44 (0)131 6507360
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Hi,

try this,

plot.new()
x=0.8
text(0.5, 0.5, bquote(rho == .(x)))


HTH,

baptiste

Quoting baptiste auguie <baptiste.auguie at googlemail.com>:

Hi,

try this,

plot.new()
x=0.8
text(0.5, 0.5, bquote(rho == .(x)))


HTH,

baptiste

Aha!

That does exactly what i wanted! Thanks!

Jose

J.delasHeras at ed.ac.uk wrote:

Quoting baptiste auguie <baptiste.auguie at googlemail.com>:

Hi,

try this,

plot.new()
x=0.8
text(0.5, 0.5, bquote(rho == .(x)))


HTH,

baptiste

Aha!

That does exactly what i wanted! Thanks!

Jose

But does it do what it should? It's customary to use
"rho" for a _population_ correlation coefficient. If your
(x,y) values represent a _sample_, then it would probably
be more appropriate to use the more mundane "r" or
perhaps "rho-hat".

Quoting Peter Ehlers <ehlers at ucalgary.ca>:

J.delasHeras at ed.ac.uk wrote:

Quoting baptiste auguie <baptiste.auguie at googlemail.com>:

Hi,

try this,

plot.new()
x=0.8
text(0.5, 0.5, bquote(rho == .(x)))


HTH,

baptiste

Aha!

That does exactly what i wanted! Thanks!

Jose

But does it do what it should? It's customary to use
"rho" for a _population_ correlation coefficient. If your
(x,y) values represent a _sample_, then it would probably
be more appropriate to use the more mundane "r" or
perhaps "rho-hat".

I'm talking rank correlation, Spearman's rho.

Jose