Regexp entities

Some entities need to match patterns rather than specific terms. For example, national identification numbers, IDs, license plates, and so on. With regexp entities , you can provide regular expressions for matching.

Compound regular expressions

Each regexp entity corresponds to a single pattern, but you can provide multiple regular expressions if they all represent variations of a single pattern. During agent training, all regular expressions of a single entity are combined with the alternation operator ( | ) to form one compound regular expression .

For example, if you provide the following regular expressions for a phone number:

• ^[2-9]\d{2}-\d{3}-\d{4}$
• ^(1?(-?\d{3})-?)?(\d{3})(-?\d{4})$

The compound regular expression becomes:

• ^[2-9]\d{2}-\d{3}-\d{4}$|^(1?(-?\d{3})-?)?(\d{3})(-?\d{4})$

The ordering of regular expressions matters. Each of the regular expressions in the compound regular expression are processed in order. Searching stops once a valid match is found. For example, for an end user expression of "Seattle":

• Sea|Seattle matches "Sea"
• Seattle|Sea matches "Seattle"

Special handling for speech recognition

If your agent uses speech recognition (also known as audio input, speech-to-text, or STT), your regular expressions will need special handling when matching letters and numbers. A spoken end-user utterance is first processed by the speech recognizer before entities are matched. When an utterance contains a series of letters or numbers, the recognizer may pad each character with spaces. In addition, the recognizer may interpret digits in word form. For example, an end-user utterance of "My ID is 123" may be recognized as any of the following:

• "My ID is 123"
• "My ID is 1 2 3"
• "My ID is one two three"

To accommodate three digit numbers, you could use the following regular expressions:

\d{3}

\d \d \d

(zero|one|two|three|four|five|six|seven|eight|nine) (zero|one|two|three|four|five|six|seven|eight|nine) (zero|one|two|three|four|five|six|seven|eight|nine)

Create a regexp entity

Limitations

The following limitations apply:

• Fuzzy matching cannot be enabled for regexp entities. These features are mutually exclusive.
• Each agent can have a maximum of 50 regexp entities.
• The compound regular expression for an entity has a maximum length of 2000 characters.