php: find variable characters in an array - php

Question

Got a varibale that holds phone number and the number have it country prefix before it and the phone number is dynamic and can be any phone number from any country.
So, I need to get the country of the phone number by matching certain characters (i.e the country prefix preceding the phone number) in the variable against the record in the DB (country prefix would be fetched into an array) holding all country prefix.
Sample:
$phoneVar = '4477809098888'; // uk - 44
$phoneVar = '15068094490'; // usa - 1
$phoneVar = '353669767954'; // ireland - 352
$phoneVar = '2348020098787'; // nigeria - 234
If the $phoneVar is assigned any phone number value, need to be able to get the country prefix out of it.
Something like this:
echo getCountryPrefix($phoneVar, $countries_prefix_array);
This would have been easy to achieve using substr
// $countryPrefix = substr($phoneVar, 0, 3);
But countries do not have the same prefix length.
Would be pleased to get help with this.

Answer 1

Something like this will work.
It's probably not accurate to your code, but I'm sure you can see the logic.
function findCountryCode($number, $country_codes) {
$country_codes = usort($country_codes, 'lsort');
foreach ($country_codes as $key => $val) {
if (substr($number, 0, strlen($val)) == $val)
return $key;
}
return false;
}
function lsort($a,$b) {
return strlen($b)-strlen($a);
}

Answer 2

Ok this is a perfect example for a state machine !
simplest way:
$prefixes = array('44' => 'UK', '1' => 'USA', '352' => 'IRELAND', '234' => 'NIGERIA');
preg_match('/^('.implode('|',array_keys($prefixes)).')/', $phoneVar, $matches);
echo $prefixes[$matches[0]];

Answer 3

You might find this schema useful.
The coding is straight-forward, if you maintain a map of prefix to country code.
Sort the prefixes, start at the back so 123 is tried before 1.

Answer 4

You can do this like following codes:
$phoneVar = '4477809098888'; // uk - 44
$county_list = array('uk' => 44, 'usa' => 1, 'ireland' => 352, 'nigeria' => 234);
foreach ($county_list as $key => $value)
{
if (preg_match('/^'.$value.'/', $phoneVar))
{
echo "Country is: ".$key;
echo "Country code: ".$value;
break;
}
}
Output
Country is: uk
Country code: 44

Answer 5

You can use preg_match() :
$phoneVar = "abcdef";
$pattern = '/^44/';
preg_match($pattern, $phoneVar, $matches, PREG_OFFSET_CAPTURE, 3);
print_r("UK : ".$matches);
This can mean lengthy code. But if its just 4 countries then this would serve your purpose.