exercism fetch php phone-number

Phone Number

Clean up user-entered phone numbers so that they can be sent SMS messages.

The North American Numbering Plan (NANP) is a telephone numbering system used by many countries in North America like the United States, Canada or Bermuda. All NANP-countries share the same international country code: 1.

NANP numbers are ten-digit numbers consisting of a three-digit Numbering Plan Area code, commonly known as area code, followed by a seven-digit local number. The first three digits of the local number represent the exchange code, followed by the unique four-digit number which is the subscriber number.

The format is usually represented as


where N is any digit from 2 through 9 and X is any digit from 0 through 9.

Your task is to clean up differently formatted telephone numbers by removing punctuation and the country code (1) if present.

For example, the inputs

should all produce the output


Note: As this exercise only deals with telephone numbers used in NANP-countries, only 1 is considered a valid country code.

Running the tests

  1. Go to the root of your PHP exercise directory, which is <EXERCISM_WORKSPACE>/php. To find the Exercism workspace run

    % exercism debug | grep Workspace
  2. Get PHPUnit if you don't have it already.

    % wget --no-check-certificate https://phar.phpunit.de/phpunit.phar
    % chmod +x phpunit.phar
  3. Execute the tests:

    % ./phpunit.phar phone-number/phone-number_test.php


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Submitting Incomplete Solutions

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