Stemming and Wildcards 101

What is Stemming?

If you have never come across stemming before, you can think of it as being a method in which you can search for a word and have related words returned. Thinking of it more technically, it is a method of producing morphological variants of a root or base word. It can reduce words such as "spraying", "sprayable", "sprayed" or "sprays" to the root word of "spray". This will allow you to search for a base word and not have to additionally include variants of that word in your query.

English stemming can be found in the settings, which you can get to by performing any search and locating the small grey cog button that is situated on the top-right of the search results page, just above your search results. This will open the settings popup window. It is switched ON by default. 

Recently, we introduced an update to our stemming logic which is more advanced and will provide you with more accurate and advanced results for the queries you perform. 

You can find more information on benefits of our new stemming logic here.

Wildcards

This is a more selective form of stemming. If you only want certain words to be stemmed, you can add an asterisk at the end of the word you want to be stemmed.

There are three wildcards, the question mark ?, the hash # and the asterisk *. Wildcards can be used anywhere within a word or simultaneously. One ? represents one character, one # represents zero or one characters and the * represents an unlimited number of characters, i.e.:

car? (will give you cars, card, care…)

car# (will give you car, cars, card, care...)

car* (will give you car, carton, carbon, cardio…)

*car (will give you railcar, turbocar, vicar, scar...)

Patsnap will search up to 10000 wildcard variations per query (1500 when combined with positional connectors). The limit is in place to ensure that you only get the most relevant search results returned.