Sort or order ICD-9 or ICD-10 codes according to published sequence

The default method will guess whether ICD-9 or ICD-10 then sort based on that type. For ICD-10 codes, note that setting short is unnecessary and ignored. All codes should consistently use the decimal divider.

sort_icd(x, decreasing = FALSE, short_code = guess_short(x), ...)

# S3 method for icd10
sort(x, decreasing = FALSE, ...)

# S3 method for icd10cm
sort(x, decreasing = FALSE, ...)

# S3 method for icd10be
sort(x, decreasing = FALSE, ...)

# S3 method for icd9
sort(x, decreasing = FALSE, short_code = guess_short(x), ...)

order.icd9(x, na.last = TRUE)

order.icd10cm(x)

order.icd10be(x)

Arguments

x	vector of ICD codes to sort or order
decreasing	Logical See sort.
short_code	single logical value which determines whether the ICD-9 code provided is in short (TRUE) or decimal (FALSE) form. Where reasonable, this is guessed from the input data.
...	arguments passed on to other functions
na.last	Logical, analogous to order, so NA drops NA. FALSE is not currently supported.

Value

For sort, a sorted vector of ICD-9 codes. Numeric, then E codes, then V codes. For order, an integer vector is returned with the order of each code.

Details

Note that sort is an S3 generic, whereas order is not. Thus we export order.icd10cm, but not sort.icd10cm, etc..

ICD-9

Sorts lists of numeric, V or E codes. Note that a simple numeric sort does not work for ICD-9 codes, since 162 > 1620, and also ‘V’ codes precede ‘E’ codes. Numeric codes are first, then ‘V’, then ‘E’. A factor is returned if a factor is given.

ICD-10-CM and ICD-10-BE

There are some codes which are sequenced out of lexicographic order, e.g., C7A and C7B are between C80 and C81; D3A is between D48 and D49.

Examples

# order ICD-10-CM is not lexicographic:
codes <- as.icd10cm(c("C7A", "C79", "C80", "C81", "C7B"))
# as the class is set, use S3 dispatch to get the right answer
sort(codes)
#> [1] "C7A" "C79" "C80" "C81" "C7B"
# or call directly, but recall S3 dispatch will only work once 'icd' is
# attached using:
library(icd)
icd:::sort.icd10cm(c("C7A", "C79", "C80", "C81", "C7B"))
#> [1] "C7A" "C79" "C80" "C81" "C7B"
stopifnot(!identical(
  order.icd10cm(as.character(codes)),
  order(codes)
))
icd::order.icd9(c("V20", NA, "100", NA, "E998", "101"))
#> [1] 3 6 1 5 2 4
codes[order.icd10cm(codes)]
#> [1] "C7A" "C79" "C80" "C81" "C7B"
# Note that base::order does NOT do S3 dispatch, so the following does not work:
codes[order(codes)]
#> [1] "C7A" "C7B" "C79" "C80" "C81"