An emm_list object is simply a list of
emmGrid objects. Such a list is returned,
for example, by emmeans with a two-sided formula or a list as its
specs argument. Several methods for this class are provided, as detailed below.
Typically, these methods just quietly do the same thing as their emmGrid
methods, using the first element of the list. You can specify which
to select a different element, or just run the corresponding emmGrid
method on object[[k]].
# S3 method for class 'emm_list'
contrast(object, ..., which = NULL)
# S3 method for class 'emm_list'
pairs(x, ..., which = NULL)
# S3 method for class 'emm_list'
test(object, ..., which = seq_along(object))
# S3 method for class 'emm_list'
confint(object, ..., which = seq_along(object))
# S3 method for class 'emm_list'
plot(x, ..., which = 1)
# S3 method for class 'emm_list'
coef(object, ..., which = NULL)
# S3 method for class 'emm_list'
linfct(object, ..., which = seq_along(object))
# S3 method for class 'emm_list'
str(object, ...)
# S3 method for class 'emm_list'
summary(object, ..., which = seq_along(object))
# S3 method for class 'emm_list'
print(x, ...)
# S3 method for class 'emm_list'
as.data.frame(x, ...)
# S3 method for class 'summary_eml'
as.data.frame(x, row.names = NULL, optional = FALSE,
which, ...)an object of class emm_list
additional arguments passed to corresponding emmGrid
method. In addition, the user may include a logical argument drop
that is akin to drop and the argument of the same name in
subscripting matrices and data frames. When drop is TRUE (the
default), then when the result is a list of length 1, the
list structure is removed.
integer vector specifying which elements to select;
if NULL,
we try to guess which elements make sense. Usually, this is all elements having
names that start with ‘em’ or ‘ls’,
or the first element if no matches are found. However, in coef.emm_list,
these are the ones we exclude.
Required arguments of as.data.frame, ignored
a list of objects returned by the corresponding emmGrid
method (thus, often, another emm_list object). However, if
which has length 1, the one result is not wrapped in a list.
summary.emm_list returns an object
of class summary_eml, which is a list of summary_emm
objects.
The as.data.frame methods return a single data frame via
as.data.frame(rbind(x)).
See also rbind.emm_list and as.data.frame.emmGrid
The plot method uses only the first element of which; the others are ignored.
No export option is provided for printing an emm_list
(see print.emmGrid). If you wish to export these objects, you
must do so separately for each element in the list.
mod <- lm(conc ~ source, data = pigs)
obj <- emmeans(mod, pairwise ~ source)
linfct(obj)
#> $emmeans
#> (Intercept) sourcesoy sourceskim
#> [1,] 1 0 0
#> [2,] 1 1 0
#> [3,] 1 0 1
#>
#> $contrasts
#> (Intercept) sourcesoy sourceskim
#> [1,] 0 -1 0
#> [2,] 0 0 -1
#> [3,] 0 1 -1
#>
coef(obj) # done only for the contrasts
#> source c.1 c.2 c.3
#> 1 fish 1 1 0
#> 2 soy -1 0 1
#> 3 skim 0 -1 -1
contrast(obj, "consec") # done only for the means
#> contrast estimate SE df t.ratio p.value
#> soy - fish 7.98 2.85 26 2.795 0.0181
#> skim - soy 5.80 2.93 26 1.979 0.1047
#>
#> P value adjustment: mvt method for 2 tests
contrast(obj, "eff", drop = FALSE) # kept as a list
#> contrast estimate SE df t.ratio p.value
#> fish effect -7.255 1.66 26 -4.362 0.0005
#> soy effect 0.725 1.66 26 0.436 0.6664
#> skim effect 6.530 1.71 26 3.823 0.0011
#>
#> P value adjustment: fdr method for 3 tests