[R] decimal places

[Duncan Murdoch]

On 24/02/2015 9:11 AM, Linh Nguyen Vaccarello wrote:
> I am very new to R and I'm trying to increase my decimal places (from 2 to
> 4) for this code:
> 
>> with(longitudinal, pairwise.wilcox.test(DV, Time,
>                                         p.adjust.method="holm",
>                                         paired=TRUE))
> 
> Right now the output is:
> 
> Pairwise comparisons using Wilcoxon signed rank test
> 
> data:  DV and Time
> 
>     yr15 yr2  yr5
> yr2 0.03 -    -
> yr5 0.03 0.05 -
> yr8 0.03 0.05 0.03

Many functions in R produce objects with a class, and there are special
methods to print many classes.  In the case of pairwise.wilcox.test the
object produced is of class "pairwise.htest".  You can see the code using

stats:::print.pairwise.htest

and you'll see it hard-codes 2 significant digits.  (Which surprises me
a bit, but I guess your p-values are all 0.030 and 0.050.)

You can edit the definition for a temporary change:

print.pairwise.htest <- function (x, digits = 5, ...)
{
    cat("\n\tPairwise comparisons using", x$method, "\n\n")
    cat("data: ", x$data.name, "\n\n")
    pp <- format.pval(x$p.value, digits, na.form = "-")
    attributes(pp) <- attributes(x$p.value)
    print(pp, quote = FALSE, ...)
    cat("\nP value adjustment method:", x$p.adjust.method, "\n")
    invisible(x)
}

Your definition of this method will override the default one, so
defining that function is enough, R will call it for printing.

Duncan Murdoch
> 
> I have tried various codes and they didn't work:
> options(digits=4)
> with(longitudinal, pairwise.wilcox.test(DV, Time,
>                                         p.adjust.method="holm",
>                                         paired=TRUE))
> 
>> with(longitudinal, pairwise.wilcox.test(DV, Time,
> + p.adjust.method="holm",
> + paired=TRUE),
> + options(digits=4))
> 
>> with(longitudinal, pairwise.wilcox.test(DV, Time,
> + p.adjust.method="holm",
> + paired=TRUE,
> + digits=4))
> 
>> with(longitudinal, pairwise.wilcox.test(DV, Time,
> + p.adjust.method="holm",
> + paired=TRUE),
> + signif(digits=4))
> 
> thanks,
> Linh
> 
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> 
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