The emm_list class

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]].

Usage

# 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, ...)

Arguments

object, x

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.

which

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.

row.names, optional

Required arguments of as.data.frame, ignored

Value

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

Note

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.

Examples

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