Report:STN/Search Syntax/Allowed Operators/Truncation or Wildcard Operators

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Truncation in STN

Truncation characters (or “wildcard symbols”) allow the searcher to represent unspecified characters in a search term in order to retrieve various forms of a word. See the Truncation article for more information on truncation. The table below shows the various truncation characters available when searching on STN.[1]

Symbol Description Example Retrieves
? Represents zero to any number of characters. Used only once, usually at the end of the term. OXID? OXIDIZE, OXIDIZED, OXIDATION
# Represents zero or one character. Can be used multiple times at the end of the term only. GROW## GROW, GROWS, GROWTH
! Represents exactly one character within a term. Can be used multiple times anywhere except the beginning of a term... T!!TH TEETH, TOOTH, TRUTH
...or one character at the end of a term. AMIN! AMINE, AMINO

More than one different wildcard character may be combined within the same term. For example, in STN it would be acceptable to search for "T!!TH?" which would retrieve results including any of the terms TEETH, TOOTH, TRUTH, TOOTHY, TRUTHS, TRUTHLESS, and TOOTHLESS. Also, the # (zero or one character) and ! (exactly one character) operators can be used repeatedly, as in the "T!!TH" example above.

Left truncation, or using truncation at the beginning of a term, is possible in some databases within STN, and only in certain search fields. Also, in certain cases, left hand and right hand truncation may be used simultaneously (a feature known as Simultaneous Left And Right Truncation or SLART).

To learn whether or not a search field in the current file allows left truncation, the user can use the command "HELP SFIELDS" at the STN command prompt. For general help using truncation, the user may type "HELP TRUNCATION" at the STN command prompt.


  1. "STN Pocket Guide." CAS website, Accessed July 20, 2011.
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