Regex to extract (austrian) street housenumber/stairs/floor/door

Question

I need to extract the housenumber with all the different constellations in austria:

|               Street name               | housenumber | stairs | floor | door |
| --------------------------------------- | ----------- | ------ | ----- | ---- |
| Lilienstr. 12a                          | 12a         |        |       |      |
| Leibnizstraße 36/28/2                   | 36          | 28     |       | 2    |
| Prager Straße 14/3/1/4                  | 14          | 3      | 1     | 4    |
| Guentherstr. 43 B                       | 43 B        |        |       |      |
| Eberhard-Leibnitz Str. 1/7              | 1           |        |       | 7    |
| Schießstätte 7/7                        | 7           |        |       | 7    |

I've already found this question: Regex to extract (german) street number.

This works if no stair/floor/door is entered. Can you help?

^[ \-0-9a-zA-ZäöüÄÖÜß.]+?\s+(\d+(\s?[a-zA-Z])?)\s*(?:$|\(|[A-Z]{2})

Answer 1

The credits for the core of the pattern using the optional capturing groups with a positive lookahead go to @JvdV as he suggested with his pattern in the comments.

As an alternative, you can get the group numbers / names in the order of the specified schedule in the question, by capturing the digits of the stairs / floor / door and asserting how many parts of a forward slash followed by a digit are directly to the right.

If the assertion fails, the pattern will try the next part as all the groups are optional.

^(?<address>(?<streetname>\h*\S.*?)\h*(?<housenumber>\d+\h*[A-Za-z]?))(?:/(?<stairs>\d+)(?=(?:/\d+){1,2}))?(?:/(?<floor>\d)(?=(?:/\d+)))?(?:/(?<door>\d+))?$

Regex demo | Php demo

In parts

• ^ Start of string
• (?<address> Group address
  • (?<streetname> Group streetname
    • \h*\S.*? Match 0+ horizontal whitespace chars, a non whitepace char to make sure address is not empty and match any char as least as possible (non greedy)
  • ) Close group streetname
  • \h* Match 0+ horizontal whitespace chars for the trailing spaces after the streetname
  • (?<housenumber> Group housenumber
    • \d+\h*[A-Za-z]? Match 1+ digits, 0+ horizontal whitespace chars and optional char a-zA-Z
  • ) Close group housenumber
• ) Close group address
• (?: Non capture group
  • /(?<stairs>\d+) Group stairs, match 1+ digits
  • (?=(?:/\d+){1,2}) Positive lookahead, assert what is at the right is 1 or 2 times / followed by 1 or 2 digits
• )? Close group and make it optional
• (?: Non capture group
  • /(?<floor>\d+) Group floor, match 1+ digits
  • (?=(?:/\d)) Positive lookahead, assert what is at the right is / followed by a digit
• )? Close group and make it optional
• (?: Non capture group
  • /(?<door>\d+) Group door, match 1+ digits
• )? Close group and make it optional
• $ End of string

Example code

$re = '~^(?<address>(?<streetname>\h*\S.*?)\h*(?<housenumber>\d+\h*[A-Za-z]?))(?:/(?<stairs>\d+)(?=(?:/\d+){1,2}))?(?:/(?<floor>\d)(?=(?:/\d+)))?(?:/(?<door>\d+))?$~m';
$strings = [
    "Lilienstr. 12a",
    "Leibnizstraße 36/28/2",
    "Prager Straße 14/3/1/4",
    "Guentherstr. 43 B",
    "Eberhard-Leibnitz Str. 1/7",
    "Schießstätte 7/7"
];

foreach ($strings as $string) {
    preg_match_all($re, $string, $matches, PREG_SET_ORDER);
    $address = array_filter($matches[0], "is_string", ARRAY_FILTER_USE_KEY); // from php 5.6
    print_r($address);
}

Output

Array
(
    [address] => Lilienstr. 12a
    [streetname] => Lilienstr.
    [housenumber] => 12a
)
Array
(
    [address] => Leibnizstraße 36
    [streetname] => Leibnizstraße
    [housenumber] => 36
    [stairs] => 28
    [floor] => 
    [door] => 2
)
Array
(
    [address] => Prager Straße 14
    [streetname] => Prager Straße
    [housenumber] => 14
    [stairs] => 3
    [floor] => 1
    [door] => 4
)
Array
(
    [address] => Guentherstr. 43 B
    [streetname] => Guentherstr.
    [housenumber] => 43 B
)
Array
(
    [address] => Eberhard-Leibnitz Str. 1
    [streetname] => Eberhard-Leibnitz Str.
    [housenumber] => 1
    [stairs] => 
    [floor] => 
    [door] => 7
)
Array
(
    [address] => Schießstätte 7
    [streetname] => Schießstätte
    [housenumber] => 7
    [stairs] => 
    [floor] => 
    [door] => 7
)