Soundex class

Encodes a string to a Soundex value. Soundex is a classic encoding scheme used to compare names that sound similar. It can also be used to find words that sound similar.

While the algorithm is fairly simple, there are several variants, so make sure you know which variant you need if working with existing data. The most notable exceptions are in census data and SQL implementations.

The implementation of this class is unique because it uses a mapping strategy with several configurable behaviors that can be enabled or disabled to support many variants. it's also possible to use a custom mapping for other languages or character sets.

For convenience, there are several static instances available for some of the more common implementations:

If you want (or need) to understand more details, here are some good references that help explain the history and variants:

Implemented types

Constructors

Soundex()
Gets the americanEncoder instance of the Soundex encoder by default.
factory
Soundex.fromMapping(Map<int, int> soundexMapping, {bool prefixesEnabled = true, bool hyphenatedPartsEnabled = true, bool ignoreHW = true, bool trackIgnored = true, int maxLength = defaultMaxLength, int paddingChar = $0, bool paddingEnabled = true})
Creates a custom Soundex instance. This constructor can be used to provide custom mappings for non-Western character sets, etc.
factory

Properties

hashCode → int
The hash code for this object.
no setterinherited
hyphenatedPartsEnabled → bool
Indicates that hyphenated parts processing is enabled. When enabled, any parts that are found are also encoded and returned as alternates.
final
ignoreHW → bool
Indicates if $H and $W should be completely ignored and not mapped at all. This is a special case for some census data.
final
maxLength → int
Maximum length of the encoding, where 0 indicates no maximum, and how much to pad if paddingEnabled.
final
paddingChar → int
The character to use for padding (when paddingEnabled is true).
final
paddingEnabled → bool
Indicates if the string will be padded. If true, the encoded output will be padded with paddingChar to the length of maxLength.
final
prefixesEnabled → bool
Indicates that prefix processing is enabled (and will be returned as PhoneticEncoding._alternate when available). This also detects the second part of a double barreled name.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
soundexMapping → Map<int, int>
The character mapping to use when encoding. A value of $nul means ignore the input character and do not encode it (e.g., vowels).
final
trackIgnored → bool
Indicates if ignored characters are tracked or completely ignored. When enabled, ignored characters still act as a separator when it occurs between consonants, otherwise they are completely ignored.
final

Methods

encode(String input) → PhoneticEncoding?
Encodes a string using the Soundex algorithm as configured.
override
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited

Static Properties

americanEncoder → Soundex
An instance of Soundex using the americanMapping mapping.
final
genealogyEncoder → Soundex
An instance of Soundex using the americanMapping mapping, but configured for the special case, and does not ignore H and W.
final
specialEncoder → Soundex
An instance of Soundex using the americanMapping mapping, but configured for the special case, and does not ignore H and W.
final

Constants

americanMapping → const Map<int, int>
This is a default mapping of the 26 letters used in US English.
defaultMaxLength → const int
Default encoding length to use.