How do you remove the letters from the end of duplicate author year biblatex citations? (Biblatex-chicago with bibtex)

Question

I am building a cv wherein I \printbibliography for given keywords for several sections. Some of the sections have 100+ bibliography entries, and there are several occasions where there are the same author and year. This is a stripped-down version of the code.

\usepackage[style=chicago-authordate, backend=bibtex, maxbibnames=50, doi=true, url=true, isbn=false, sorting=ydnt]{biblatex}
\bibliography{sample.bib}
\begin{document}
\nocite{*}
\section{A}
\printbibliography[keyword={keywordA}, heading=none]
\section{B}
\printbibliography[keyword={keywordB}, heading=none]
\end{document}

Of course, the bibliography prints those entries as "Author. YEARa." e.g.,

Taylor, Sarah and Joe Hoya. 2010a. "Here's one article title."

-- 2010b. "This is a different article."

-- 2010c. "A third article."

But I need it to look like this:

Taylor, Sarah and Joe Hoya. 2010. "Here's one article title."

-- 2010. "This is a different article."

-- 2010. "A third article."

or this:

Taylor, Sarah and Joe Hoya. 2010. "Here's one article title."

Taylor, Sarah and Joe Hoya. 2010. "This is a different article."

Taylor, Sarah and Joe Hoya. 2010. "A third article."

---

Is this possible? Especially while using \printbibliography?

Answer 1

When I turn your code into an MWE I do not get any letters after dates, but the dates are moved to the end of the entry. That is with biblatex-chicago v2.1 (2021-03-27).

\documentclass[american]{article}
\usepackage[T1]{fontenc}
\usepackage{babel}
\usepackage{csquotes}
\usepackage[
  backend=bibtex,
  style=chicago-authordate,
  sorting=ydnt,
  maxbibnames=50,
  doi=true, url=true, isbn=false,
]{biblatex}
\addbibresource{biblatex-examples.bib}
\begin{document}
\nocite{knuth:ct:a,knuth:ct:b,knuth:ct:c,sigfridsson,worman,geer}
\printbibliography
\end{document}

This is due to the fact that in the example, the biblatex-chicago style is loaded directly via biblatex and not as recommended for biblatex-chicago via the wrapper package.

\documentclass[american]{article}
\usepackage[T1]{fontenc}
\usepackage{babel}
\usepackage{csquotes}
\usepackage[
  authordate,
  backend=bibtex,
  sorting=ydnt,
  maxbibnames=50,
  doi=true, url=true, isbn=false,
]{biblatex-chicago}
\addbibresource{biblatex-examples.bib}
\begin{document}
\nocite{knuth:ct:a,knuth:ct:b,knuth:ct:c,sigfridsson,worman,geer}
\printbibliography
\end{document}

It is possible that older versions of biblatex-chicago behaved slightly differently, so that the date letter (courtesy of labeldateparts) is also present when the style is not called via biblatex-chicago.

Here is a solution that works with my newer version of biblatex-chicago, but it should also work for older versions. The idea is to just discard the extradate info.

\documentclass[american]{article}
\usepackage[T1]{fontenc}
\usepackage{babel}
\usepackage{csquotes}
\usepackage[
  authordate,
  backend=bibtex,
  sorting=ydnt,
  maxbibnames=50,
  doi=true, url=true, isbn=false,
]{biblatex-chicago}
\DeclareFieldInputHandler{extradate}{\def\NewValue{}}
\addbibresource{biblatex-examples.bib}
\begin{document}
\nocite{knuth:ct:a,knuth:ct:b,knuth:ct:c,sigfridsson,worman,geer}
\printbibliography
\end{document}