icd9Children: Expand ICD-9 codes to all possible sub-codes
In jackwasey/icd9: Tools for Working with ICD-9 Codes, and Finding Comorbidities

Description Usage Arguments See Also Examples

Expand ICD-9 codes to all possible sub-codes

icd9Children(icd9, isShort = icd9GuessIsShort(icd9), onlyReal = TRUE,
  onlyBillable = FALSE)

icd9ChildrenShort(icd9Short, onlyReal = TRUE, onlyBillable = FALSE)

icd9ChildrenDecimal(icd9Decimal, onlyReal = TRUE, onlyBillable = FALSE)

`icd9`	is a character vector or factor of ICD-9 codes. If fewer than five characters is given in a code, then the digits are greedily assigned to hundreds, then tens, then units, before the decimal parts. E.g. "10" becomes "010", not "0010".
`isShort`	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.
`onlyReal`	single logical value, if TRUE, will limit the search to those codes which appear in the master list, not just syntactically valid codes. Since nearly valid, out-dated or new codes may be missed, not limiting to 'real' values will be useful. Ultimately, there will need to be annual (and all-time) master lists of codes and the ability to test against a given master list given the year of the ICD-9 coding.
`onlyBillable`	single logical value, if `TRUE`, describes the input data, stating that it only contains billable codes. Usually, the function will try to guess this, but if you know in advance what they should be, the functions can optionally warn if this is incorrect, and save some computation time. The billable codes are derived from the CMS list. The most recent version is used by default.
`icd9Short`	is a character vector of ICD-9 codes. If fewer than five characters is given in a code, then the digits are greedily assigned to hundreds, then tens, then units, before the decimal parts. E.g. "10" becomes "010", not "0010"
`icd9Decimal`	character vector of ICD-9 codes. If fewer than five characters is given in a code, then the digits are greedily assigned to hundreds, then tens, then units, before the decimal parts. E.g. "10" becomes "010", not "0010"

Other ICD-9 ranges: icd9Condense, icd9ExpandMinor, icd9ExpandRange

library(magrittr)
icd9ChildrenShort("10201", FALSE) # no children other than self
icd9Children("0032", FALSE) # guess it was a short, not decimal code
icd9ChildrenShort("10201", TRUE) # empty because 102.01 is not meaningful
icd9ChildrenShort("003", TRUE) %>% icd9ExplainShort(doCondense = FALSE)
icd9ChildrenDecimal("100.0")
icd9ChildrenDecimal("100.00")
icd9ChildrenDecimal("2.34")