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Phone Number Normalisation

Source: vignettes/phone-normalization.Rmd
phone-normalization.Rmd

Overview

SELMA stores phone numbers in various formats. standardize_phone() uses the dialvalidator package (powered by Google’s libphonenumber metadata) to parse, validate, and format phone numbers to E.164 international format.

By default, numbers without a country code are tried as NZ first, then AU. This handles the common case of SELMA instances with students across both countries.

Examples

New Zealand (+64) 

library(selmaR)

standardize_phone("021 123 4567")     # NZ mobile with leading 0
#> [1] "+64211234567"
#> "+64211234567"

standardize_phone("0211234567")       # No spaces
#> [1] "+64211234567"
#> "+64211234567"

standardize_phone("+64211234567")     # Already international
#> [1] "+64211234567"
#> "+64211234567"

standardize_phone("211234567")        # Mobile without leading 0
#> [1] "+64211234567"
#> "+64211234567"

Australia (+61)

AU numbers with a +61 prefix work directly. Local AU numbers (e.g. 04xx) are automatically detected via the NZ-then-AU fallback — 04 is not a valid NZ prefix, so dialvalidator correctly parses it as Australian:

standardize_phone("+61412345678")     # Already international
#> [1] "+61412345678"
#> "+61412345678"

standardize_phone("0412345678")       # AU local — detected automatically
#> [1] "+61412345678"
#> "+61412345678"

Invalid Numbers

Numbers that fail validation in all regions are returned as NA:

standardize_phone("1234")            # Too short
#> [1] NA
#> NA

standardize_phone(NA)                # NA passthrough
#> [1] NA
#> NA

standardize_phone("")                # Empty string
#> [1] NA
#> NA

Vectorised Usage

Use standardize_phones() for vectors — handles mixed NZ and AU numbers:

phones <- c("021 123 4567", "0412345678", "+61412345678", NA)
standardize_phones(phones)
#> [1] "+64211234567" "+61412345678" "+61412345678" NA
#> [1] "+64211234567" "+61412345678" "+61412345678" NA

Use with dplyr 

library(dplyr)

students |>
  mutate(
    mobile_std = standardize_phone(mobilephone),
    secondary_std = standardize_phone(secondaryphone)
  )

Custom Regions

Override the default fallback regions if your student population differs:

# Only try AU (no NZ fallback)
standardize_phones(phones, default_regions = "AU")

# Try NZ, AU, then UK
standardize_phones(phones, default_regions = c("NZ", "AU", "GB"))