How to use the enumerate function to label the items in circled numbers?

Question

I want to typeset a piece of document containing this format:

I know that it can be done by adding each label separately using pitfont, but I have too many of the labelled items and typesetting each and aligning them is a hard job. I wonder if this can be done through customizing the enumerate function.

Answer 1

A simple solution with enumitem and the circledsteps packages:

    \documentclass{article}
    \usepackage{enumitem}
    \usepackage{circledsteps}
\begin{document}

  \begin{enumerate}[label = \Circled{\arabic*}, font=\sffamily]
    \item Test
    \item Another test
    \item Still another test
    \item A last test
    \end{enumerate}

\end{document} 

Answer 2

you can say:

\documentclass{article}
\usepackage{enumitem}
\usepackage{tikz}
\protected\def\circled#1{%
\tikz[baseline]{\node[anchor = base,inner sep = 0pt,draw,circle]{#1};}%
}
\begin{document}
  \begin{enumerate}[label = \circled{\arabic*}]
    \item test
    \item test
    \begin{enumerate}[label = \circled{\roman*}]
      \item test
      \item test
    \end{enumerate}
  \end{enumerate}
\end{document}