extract subset(s) from ICD data

exactly the same as using x[n] or x[[n]] but preserves the ICD classes in result

# S3 method for icd9
[(x, ...)

# S3 method for icd9
[[(x, ...)

# S3 method for icd10
[(x, ...)

# S3 method for icd10
[[(x, ...)

Arguments

x	input data with list, vector, factor, and class set to an ICD type.
...	arguments passed on to other functions

Methods (by class)

• icd9: Extract ICD-9 codes

• icd9: Extract ICD-9 codes

• icd10: Extract ICD-10 codes

• icd10: Extract ICD-10 codes

Examples

x <- list(my_codes = as.icd9(c("V10.1", "441.1")))
x[1]
#> $my_codes
#> [1] "V10.1" "441.1"
#> 
x[[1]]
#> [1] "V10.1" "441.1"
x[[1]][2]
#> [1] "441.1"
# subsetting a list should give the underlying data structure type,
# preserving the ICD class
stopifnot(!inherits(x[[1]], "list"))
stopifnot(!inherits(x[[1]][2], "list"))

y <- as.icd10(c("A01", "B0234"))
y[2]
#> [1] "B0234"
y[[2]]
#> [1] "B0234"
stopifnot(inherits(y[2], "icd10"))
stopifnot(inherits(y[[2]], "icd10"))