Modify subsection numbering in KOMA

Question

In my scrartcl, I want to modify the subsection numbering as UNIT I, without being preceded by section numbering. How I can do that?

An MWE is:

\documentclass{scrartcl}
\begin{document}
\section{Hello}
\subsection{World}

Instead of \textbf{1.1 World}, I want \textbf{Unit I. World}
\end{document}

Answer 1

I literally googeled "koma latex change subsection" and used the first hit :).

\documentclass{scrartcl}

% https://tex.stackexchange.com/questions/353008
\renewcommand*\thesubsection{Unit \Roman{subsection}}

\begin{document}

\section{Hello}
\subsection{World}

\end{document}

Answer 2

If your use case doesn't require you to create cross-references to the "units", @Dr.ManuelKuehner's simple and straightforward answer is perfectly adequate.

In, however, if you foresee a need to create cross-references of the units, it's better not to incorporate the word "Unit" directly into the macro \thesubsection. Instead, it would be better to make use of the low-level LaTeX command \@seccntformat; see below for an implementation of this idea. If you pursue this approach, as an added bonus you can make use of the cross-referencing capabilities of the cleveref package, e.g., use a \cref or \Cref command to create a cross-referencing call-out to multiple objects in one go.

Incidentally, the \@seccntformat approach works equally well with the Koma-Script document classes and with the "basic" LaTeX document classes (article, report and book).

\documentclass{scrartcl}

% Method proposed in "The LaTeX Companion", 2nd ed.:
\makeatletter
\def\@seccntformat#1{\@ifundefined{#1@cntformat}%
    {\csname the#1\endcsname\space}%    default
    {\csname #1@cntformat\endcsname}}%  enable individual control
\newcommand\subsection@cntformat{Unit \thesubsection\@.\space} % subsection level
\makeatother

\renewcommand\thesubsection{\Roman{subsection}}

\usepackage{cleveref} % for \cref and \Cref macros
\crefname{subsection}{unit}{units} % label to be used in cross-references

\begin{document}
\section{Hello}       \label{sec:hello}
\subsection{World}    \label{sec:world}
\subsection{Solar System} \label{sec:system}
\subsection{Galaxy}   \label{sec:galaxy}
\subsection{Universe} \label{sec:universe}

As required, the first subsection header says \textbf{Unit I\@. World}.

\medskip
\noindent
As shown in \Cref{sec:world,sec:galaxy,sec:universe} of \Cref{sec:hello}, \dots
\end{document}