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Basically, the Soundex algorithm converts each string into a numeric code
that begins with the first letter of the string. So if you had the name Harry,
the Soundex algorithm might convert that name into the code H600 by following
these steps:
1. Capitalize all letters in the string.
2. Retain the first letter of the word.
3. Change all occurrences of the following letters to 0 (zero):
A, E, I, O, U, H, W, Y
4. Replace any letters with the following numbers:
1 = B, F, P, V
2 = C, G, J, K, Q, S, X, Z
3 = D, T
4 = L
5 = M, N
6 = R
5. Replace all pairs of identical digits with a single digit, such as replacing
66 with just 6.
6. Remove all zeros from the string.
7. Pad the string with trailing zeros so the entire Soundex code consists
of the following format:
Table 3-2 shows how the Soundex algorithm calculates identical Soundex
codes for the strings Harry and Hairy.
Table 3-2
Calculating a Soundex Code
Soundex Algorithm Step String #1 (Harry) String #2 (Hairy)
1 HARRY HAIRY
2 H H
3 H0RR0 H00R0
4 H0660 H0060
5 H060 H060
6 H6 H6
7 H600 H600