extract and set group names

group_names(x, value)

group_names(x) <- value

# Default S3 method
group_names(x, value)

# Default S3 method
group_names(x) <- value

# S3 method for class 'incidence'
group_names(x, value = NULL)

# S3 method for class 'incidence'
group_names(x) <- value

Arguments

x: an incidence() object.
value: character vector used to rename groups

Value

an integer indicating the number of groups present in the incidence object.

Details

This accessor will return a

Examples

i <- incidence(dates = sample(10, 100, replace = TRUE), 
               interval = 1L,
               groups = sample(letters[1:3], 100, replace = TRUE))
i
#> <incidence object>
#> [100 cases from days 1 to 10]
#> [3 groups: a, b, c]
#> 
#> $counts: matrix with 10 rows and 3 columns
#> $n: 100 cases in total
#> $dates: 10 dates marking the left-side of bins
#> $interval: 1 day
#> $timespan: 10 days
#> $cumulative: FALSE
#> 
group_names(i)
#> [1] "a" "b" "c"

# change the names of the groups
group_names(i) <- c("Group 1", "Group 2", "Group 3")
i
#> <incidence object>
#> [100 cases from days 1 to 10]
#> [3 groups: Group 1, Group 2, Group 3]
#> 
#> $counts: matrix with 10 rows and 3 columns
#> $n: 100 cases in total
#> $dates: 10 dates marking the left-side of bins
#> $interval: 1 day
#> $timespan: 10 days
#> $cumulative: FALSE
#> 

# example if there are mistakes in the original data, e.g. 
# something is misspelled
set.seed(50)
grps <- sample(c("child", "adult", "adlut"), 100, replace = TRUE, prob = c(0.45, 0.45, 0.05))
i <- incidence(dates = sample(10, 100, replace = TRUE), 
               interval = 1L,
               groups = grps)
colSums(get_counts(i))
#> adlut adult child 
#>     6    49    45 

# If you change the name of the mis-spelled group, it will be merged with the
# correctly-spelled group
gname <- group_names(i)
gname[gname == "adlut"] <- "adult"
# without side-effects
print(ii <- group_names(i, gname))
#> <incidence object>
#> [100 cases from days 1 to 10]
#> [2 groups: adult, child]
#> 
#> $counts: matrix with 10 rows and 2 columns
#> $n: 100 cases in total
#> $dates: 10 dates marking the left-side of bins
#> $interval: 1 day
#> $timespan: 10 days
#> $cumulative: FALSE
#> 
colSums(get_counts(i))  # original still has three groups
#> adlut adult child 
#>     6    49    45 
colSums(get_counts(ii))
#> adult child 
#>    55    45 
# with side-effects
group_names(i) <- gname
colSums(get_counts(i))
#> adult child 
#>    55    45