This usually just entails removing the decimal point, but also does some limited validation and tidying up. Missing leading zeroes will be added for correctness of the shortened codes.
decimal_to_short(x)# S3 method for icd9
decimal_to_short(x)
# S3 method for icd10
decimal_to_short(x)
# S3 method for icd10cm
decimal_to_short(x)
# S3 method for default
decimal_to_short(x)
ICD codes
icd9: convert ICD-9 codes from decimal to short
format
icd10: convert ICD-10 codes from decimal to short
format
icd10cm: convert ICD-10-CM codes from decimal to short
format
default: Guess ICD version and convert decimal to
short format
Other ICD data conversion: comorbid_df_to_mat,
  comorbid_mat_to_df, convert,
  long_to_wide,
  short_to_decimal,
  wide_to_long