getLengthOfNationalDestinationCode() public method

$phoneUtil = PhoneNumberUtil::getInstance(); $number = $phoneUtil->parse("18002530000", "US"); $nationalSignificantNumber = $phoneUtil->getNationalSignificantNumber($number); $nationalDestinationCodeLength = $phoneUtil->getLengthOfNationalDestinationCode($number); if ($nationalDestinationCodeLength > 0) { $nationalDestinationCode = substr($nationalSignificantNumber, 0, $nationalDestinationCodeLength); $subscriberNumber = substr($nationalSignificantNumber, $nationalDestinationCodeLength); } else { $nationalDestinationCode = ""; $subscriberNumber = $nationalSignificantNumber; } Refer to the unit tests to see the difference between this function and {@link #getLengthOfGeographicalAreaCode}.
public getLengthOfNationalDestinationCode ( PhoneNumber $number ) : integer
$number PhoneNumber the PhoneNumber object for which clients want to know the length of the NDC.
return integer the length of NDC of the PhoneNumber object passed in.
 public function testGetLengthOfNationalDestinationCode()
 {
     // Google MTV, which has national destination code (NDC) "650".
     $this->assertEquals(3, $this->phoneUtil->getLengthOfNationalDestinationCode(self::$usNumber));
     // A North America toll-free number, which has NDC "800".
     $this->assertEquals(3, $this->phoneUtil->getLengthOfNationalDestinationCode(self::$usTollFree));
     // Google London, which has NDC "20".
     $this->assertEquals(2, $this->phoneUtil->getLengthOfNationalDestinationCode(self::$gbNumber));
     // A UK mobile phone, which has NDC "7912".
     $this->assertEquals(4, $this->phoneUtil->getLengthOfNationalDestinationCode(self::$gbMobile));
     // Google Buenos Aires, which has NDC "11".
     $this->assertEquals(2, $this->phoneUtil->getLengthOfNationalDestinationCode(self::$arNumber));
     // An Argentinian mobile which has NDC "911".
     $this->assertEquals(3, $this->phoneUtil->getLengthOfNationalDestinationCode(self::$arMobile));
     // Google Sydney, which has NDC "2".
     $this->assertEquals(1, $this->phoneUtil->getLengthOfNationalDestinationCode(self::$auNumber));
     // Google Singapore, which has NDC "6521".
     $this->assertEquals(4, $this->phoneUtil->getLengthOfNationalDestinationCode(self::$sgNumber));
     // An invalid US number (1 digit shorter), which has no NDC.
     $this->assertEquals(0, $this->phoneUtil->getLengthOfNationalDestinationCode(self::$usShortByOneNumber));
     // A number containing an invalid country calling code, which shouldn't have any NDC.
     $number = new PhoneNumber();
     $number->setCountryCode(123)->setNationalNumber(6502530000);
     $this->assertEquals(0, $this->phoneUtil->getLengthOfNationalDestinationCode($number));
     // An international toll free number, which has NDC "1234".
     $this->assertEquals(4, $this->phoneUtil->getLengthOfNationalDestinationCode(self::$internationalTollFree));
 }