ItuCodes 
Helper library for telephone country codes based on the official International Telecommunications Union specifications:
- List of ITU-T Recommendation E.164 assigned country codes
- LIST OF ITU-T RECOMMENDATION E.164 ASSIGNED COUNTRY CODES (POSITION ON 1 NOVEMBER 2011)
Country code lookup based on official ISO-3166-1 specifications:
The main goal of this library is to closely match the latest official specifications from the ITU, ISO, NANPA and other governing bodies relating to calling codes. If you find any discrepancies in the data, please let me know!
Some complicating factors when dealing with calling codes:
- In North America, 25 countries and territories follow the North American Numbering Plan and share the ITU code '1'.
- Russia and Kazakhstan share the ITU code '7'.
- The ITU does not use ISO 3166 alpha-2 codes to specify countries or regions in its documents.
- In general, each ITU code corresponds to exactly one ISO 3166 code. However, there are exceptions. For examples, the Australian External Territories have a single ITU code of '672', but have 4 distinct ISO 3166 codes (CC, CX, HM, NF).
Usage:
# The following methods are provided:
# ItuCodes.country_for(full_or_partial_number)
# ItuCodes.find_by_itu_code(code)
# ItuCodes.find_by_name(country_name)
# ItuCodes.valid_code?(exact_itu_code)
# ItuCodes.parse_code(full_or_partial_number)
# ItuCodes.parse_number(full_or_partial_number)
# ItuCodes.iso2itu(iso_2_letter_country_code)
# ItuCodes.itu2iso(exact_itu_code)
# ItuCodes.compatriots?(full_or_partial_number1, full_or_partial_number2)
# ItuCodes.north_american_area_code_for
# Examples
# Any full or partial number will work
ItuCodes.country_for('33')
# => "France"
# Country names are returned EXACTLY as specified in ITU E.164 document
ItuCodes.country_for('18184442222')
# => "United States of America"
ItuCodes.country_for('7')
# => [ "Kazakhstan (Republic of)", "Russian Federation" ]
ItuCodes.find_by_itu_code '995'
# => "Georgia"
ItuCodes.find_by_itu_code '123123995'
# => nil
# Name should match EXACTLY as specified in ITU E.164 document
# ItuCodes.iso2itu accepts 2 letter ISO 3166 codes
ItuCodes.find_by_name 'France'
# => "33"
ItuCodes.find_by_name 'Erewhon'
# => nil
ItuCodes.valid_code? '8392813'
# => false
ItuCodes.valid_code? '7'
# => true
ItuCodes.parse_code '18185558888'
# => 1
# non-numeric characters are ignored
ItuCodes.parse_code '1 (818) 555-8888'
# => "1"
ItuCodes.parse_code '822'
# => "82"
ItuCodes.parse_code '4'
# => nil
ItuCodes.parse_number '18185558888'
# => "8185558888"
# non-numeric characters are ignored
ItuCodes.parse_number '1 (818) 555-8888'
# => "8185558888"
# Convert from and to ISO 2-letter country codes:
ItuCodes.iso2itu('US')
# => "1"
# Convert from and to ISO 2-letter country codes:
ItuCodes.itu2iso('1')
# => ["AS", "AI", "AG", "BS", "BB", "BM", "VG", "CA", "KY", "DM", "DO", "GD", "GU", "JM", "MS", "MP", "PR", "KN", "LC", "VC", "SX", "TT", "TC", "US", "VI"]
# Mexico
# ISO 3361 code : MX
# ITU code : 52
ItuCodes.iso2itu('MX')
# => "52"
ItuCodes.itu2iso('52')
# => "MX"
# Despite the same 1st digit,
# these are for different
# countries ...
ItuCodes.compatriots? '822', '811'
# => false
# ... but these are for
# the same country ...
ItuCodes.compatriots? '1984', '1985'
# => true
# ... and then there's the
# North American 'situation' ...
ItuCodes.compatriots? '1264', '1818'
# => false
# parse the area code for North American numbers:
ItuCodes.north_american_area_code_for '18185551234'
# => '1818'
# returns nil if the passed number is not North American
ItuCodes.north_american_area_code_for '332233'
# => nil