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Table 5 Orthographic Features.

From: Extraction of semantic biomedical relations from text using conditional random fields

Orthographic Feature Regular Expression
Init Caps [A-Z].*
Init Caps Alpha [A-Z][a-z]*
All Caps [A-Z]+
Caps Mix [A-Za-z]+
Has Digit .*[0-9].*
Single Digit [0-9]
Double Digit [0-9][0-9]
Natural Number [0-9]+
Real Number [-\+][[0-9]+[\.,]+[0-9].,]+
Alpha-Numeric [A-Za-z0-9]+
Roman [ivxdlcm]+|[IVXDLCM]+
Has Dash .*-.*
Init Dash -.*
End Dash .*-
Punctuation [,\.;:\?!-\+"]
Greek (alpha|beta|...|omega)
Has Greek .*\b(alpha|beta|...|omega)\b.*
Mutation Pattern \w*\d+-*\D+
  1. Orthographic features and their corresponding regular expressions used in the experiments.