how to pass arguments to panel.cor in pairs()

On 09/10/2018 10:53 AM, Jinsong Zhao wrote:

Hi there,

Here is the panel.cor function from ?pairs:

????? panel.cor <- function(x, y, digits = 2, prefix = "", cex.cor, ...)
????? {
????????? usr <- par("usr"); on.exit(par(usr))
????????? par(usr = c(0, 1, 0, 1))
????????? r <- abs(cor(x, y))
????????? txt <- format(c(r, 0.123456789), digits = digits)[1]
????????? txt <- paste0(prefix, txt)
????????? if(missing(cex.cor)) cex.cor <- 0.8/strwidth(txt)
????????? text(0.5, 0.5, txt, cex = cex.cor * r)
????? }

in the following code, pairs use the panel.cor defined above:

????? pairs(USJudgeRatings, lower.panel = panel.smooth, upper.panel = 
panel.cor,
??????????? gap=0, row1attop=FALSE)

I try to change prefix = "" to prefix = "r = ", something like:

????? pairs(USJudgeRatings, lower.panel = panel.smooth, upper.panel = 
panel.cor, prefix = "r = ",
??????????? gap=0, row1attop=FALSE)

I got lots of warnings.

How to change prefix to something else, but not change the defined 
panel.cor? Thanks!

Since panel.cor is not a base function, just a function defined in the 
example, you could just modify it.

If you want the regular one sometimes and a custom one other times,
you could make your own panel function:

 ? panel.cor2 <- function(...) panel.cor(..., prefix = "r = ")

Then use


 ? pairs(USJudgeRatings, lower.panel = panel.smooth, upper.panel = 
panel.cor2, gap=0, row1attop=FALSE)