[R] how to pass arguments to panel.cor in pairs()

[Jinsong Zhao]

On 2018/10/9 23:22, Duncan Murdoch wrote:
> 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)
> 

That is what I want to know. Thanks a lot.

Best,
Jinsong