Normalize EINs to Canonical IRS Format

Coerces a vector of Employer Identification Numbers (EINs) to the canonical IRS display format `XX-XXXXXXX` (10 characters, two digits, hyphen, seven digits). Useful for users joining external data (CSV exports, spreadsheets, API responses) against the BMF returned by [nccs_read()], whose `ein` column is already normalized upstream.

Usage

nccs_normalize_ein(x)

Arguments

x

A character or numeric vector of EINs in any format (`"123456789"`, `"12-3456789"`, `123456789`, `"1234567"`, etc.).

Value

A character vector the same length as `x`, with each element either in `XX-XXXXXXX` form or `NA_character_`.

Details

The function strips all non-digit characters, left-pads to nine digits with zeros (to recover EINs that lost a leading zero during numeric coercion), and inserts the hyphen at position 3. Values that cannot be reduced to a non-empty digit string of nine or fewer characters become `NA_character_`.

Pure base-R, no side effects, no in-place mutation.

Examples

nccs_normalize_ein(c("123456789", "12-3456789", 123456789))
#> [1] "12-3456789" "12-3456789" "12-3456789"
# All three become "12-3456789".

nccs_normalize_ein("1234567")       # leading zeros restored -> "00-1234567"
#> [1] "00-1234567"
nccs_normalize_ein(c("abc", NA))    # both become NA
#> [1] NA NA