removes white space and separates V or E if present.
icd9_extract_alpha_numeric(x)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".
vector or matrix, with first item of each row (or whole vector) containing V, E or "". The second part contains the numeric parts of the code, which may include a decimal point.