biblatex: remove field from specific entry

Question

I found various ways to remove a field from some entry types. I need to remove the url from some entries but not other of the same type. I try to find in the biblatex manual if it is possible to select entries by their key, but I was unsuccessful. Is there a way to do it at biber or biblatex level?

Answer 1

You can use \iffieldequalstr{entrykey}{<key>} to select the entry with key <key>.

\AtEveryBibitem{%
  \iffieldequalstr{entrykey}{tric}
    {\clearfield{url}\clearfield{urlyear}}
    {}%
}

Deletes URL and URL date for an entry called tric.

If you want to go by type instead use

\AtEveryBibitem{%
  \ifentrytype{article}
    {\clearfield{url}\clearfield{urlyear}}
    {}%
}

This deletes URL and URL date for @articles.

---

Alternatively, you can use Biber's sourcemapping. The advantage of sourcemapping is that the data is removed on the input level. So that it is not considered for various extra calculations like labelyear, labelname, etc.

You can clear a particular entry by matching the entrykey

\DeclareSourcemap{
  \maps{
    \map{
      \step[fieldsource=entrykey, match=\regexp{\Actan\Z}, final]
      \step[fieldset=url, null]
      \step[fieldset=urldate, null]
    }
  }
}

For type-specific mapping use \pertype.

\DeclareSourcemap{
  \maps{
    \map{
      \pertype{article}
      \step[fieldset=url, null]
      \step[fieldset=urldate, null]
    }
  }
}