How to extract p-value from "summary.glht"

Question

I want to extract value from Pr(>|t|) column

library(lsmeans)    
warp.lm = lm(breaks ~ wool * tension, data = warpbreaks)
toP<-lsmeans(warp.lm, pairwise ~ wool | tension, glhargs=list())
toP[[2]]

         Simultaneous Tests for General Linear Hypotheses

Fit: lm(formula = breaks ~ wool * tension, data = warpbreaks)

Linear Hypotheses:
               Estimate Std. Error t value Pr(>|t|)   
A - B | L == 0   16.333      5.157   3.167  0.00797 **
A - B | M == 0   -4.778      5.157  -0.926  0.73187   
A - B | H == 0    5.778      5.157   1.120  0.60282   
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 
(Adjusted p values reported -- single-step method)

How to do this? class(toP[[2]]) say it "summary.glht" "glht". There are $pvalues in toP[[2]][9] but toP[[2]][9]$pvalues give NULL

Answer 1

If you want to know the "elements" you can access for a given object, don't use class, use names :

R> names(toP[[2]])
[1] "model"       "linfct"      "rhs"         "coef"        "vcov"       
[6] "df"          "alternative" "type"        "test"       

Here, you can see that there is an element called test. Let's look at it :

R> names(toP[[2]]$test)
[1] "pfunction"    "qfunction"    "coefficients" "sigma"       
[5] "tstat"        "pvalues"      "type"        

Hmm, there's an element called pvalues. Sounds good. You can access it with :

R> toP[[2]]$test$pvalues
[1] 0.007954354 0.731843623 0.602840958
attr(,"error")
[1] 7.579683e-05

And here you get your p-values...

Another way to get the structure of an object is to use the str(). Applied to your case (str(toP[[2]])) it leads to a bit long output, but could have allowed you to directly determine the way to access your p-values.