[Tex/LaTex] Adding a period after section

sectioningtitlesec

I have 

\usepackage{titlesec}
\titleformat{\section}[runin]
{\normalfont\Large\bfseries}{\thesection}{1em}{}
\titleformat{\subsection}[runin]
{\normalfont\large\bfseries}{\thesubsection}{1em}{}

which moves the text up after the section (and subsection). How can I add a period after the section title so that I get:

2.3 Section title. Text of paragraph…

Best Answer

Two ways.

The last argument of \titleformat can contain a macro that takes the title as its argument. So

\usepackage{titlesec}
\titleformat{\section}[runin]
  {\normalfont\Large\bfseries}
  {\thesection}
  {1em}
  {\addperiod}
\titleformat{\subsection}[runin]
  {\normalfont\large\bfseries}
  {\thesubsection}
  {1em}
  {\addperiod}
\newcommand{\addperiod}[1]{#1.}

Alternatively, use the explicit option; in this case you have to use #1 in the last argument to \titleformat to stand for the title.

\usepackage[explicit]{titlesec}
\titleformat{\section}[runin]
  {\normalfont\Large\bfseries}
  {\thesection}
  {1em}
  {#1.}
\titleformat{\subsection}[runin]
  {\normalfont\large\bfseries}
  {\thesubsection}
  {1em}
  {#1.}

The first way is more customizable.

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