Examples of ColognePhonetic

kipedia.org/wiki/K%C3%B6lner_Phonetik">Kölner Phonetik (Cologne Phonetic) algorithm issued by Hans Joachim Postel in 1969.

The Kölner Phonetik is a phonetic algorithm which is optimized for the German language. It is related to the well-known soundex algorithm.

Algorithm

Step 1:

After preprocessing (conversion to upper case, transcription of germanic umlauts, removal of non alphabetical characters) the letters of the supplied text are replaced by their phonetic code according to the following table.

Letter	Context	Code
A, E, I, J, O, U, Y		0
H		-
B		1
P	not before H	1
D, T	not before C, S, Z	2
F, V, W		3
P	before H	3
G, K, Q		4
C	at onset before A, H, K, L, O, Q, R, U, X
C	before A, H, K, O, Q, U, X except after S, Z
X	not after C, K, Q	48
L		5
M, N		6
R		7
S, Z		8
C	after S, Z
	at onset except before A, H, K, L, O, Q, R, U, X
	not before A, H, K, O, Q, U, X
D, T	before C, S, Z
X	after C, K, Q

(Source: Wikipedia (de): Kölner Phonetik -- Buchstabencodes)

Example:

{@code "M}ü {@code ller-L}ü {@code denscheidt" => "MULLERLUDENSCHEIDT" => "6005507500206880022"}

Step 2:
Collapse of all multiple consecutive code digits.
Example:
{@code "6005507500206880022" => "6050750206802"}
Step 3:
Removal of all codes "0" except at the beginning. This means that two or more identical consecutive digits can occur if they occur after removing the "0" digits.
Example:
{@code "6050750206802" => "65752682"}

@see Wikipedia (de): Kölner Phonetik (in German) @author Apache Software Foundation @since 1.5