Alignment of enumerate (numbered by subsection) and the existing text

Question

I have a document full of lists which I need to refer to later in the document. Therefore I number my lists (enumerate) by subsections. I have chosen to specify this globally by this line in the preamble:

\renewcommand*{\theenumi}{\thesubsection.\arabic{enumi}}

This gives me the result I want, but because each item now consists of 4 digits (chapter.section.subsection.item), some of the numbers end up in the left margin:

I would like the numbers of enumerate to (left) align with the rest of the document text (including subsection numbers as seen in the picture above). How is this done globally, since I have a massive amount of lists?

If relevant: I am using memoir.

Answer 1

Similar to Harish's answer, but there's no need for

\renewcommand*{\theenumi}{\thesubsection.\arabic{enumi}}

You can simply define

\setlist[enumerate]{leftmargin=*,align=left,label=\thesubsection.\arabic*.}

MWE:

\documentclass{memoir}

\setcounter{secnumdepth}{3}

\usepackage{enumitem}
\setlist[enumerate]{leftmargin=*,align=left,label=\thesubsection.\arabic*.}

\begin{document}

\chapter{A chapter}
\section{A section}
\subsection{A subsection}
\begin{enumerate}
  \item aaa
  \item bbb
  \item ccc
\end{enumerate}
\end{document} 

If you need it only for a few enumerate environments, instead of setting globally

\setlist[enumerate]{leftmargin=*,align=left,label=\thesubsection.\arabic*.}

use these settings locally by issuing

\begin{enumerate}[leftmargin=*,align=left,label=\thesubsection.\arabic*.]

Note that you may need to load enumitem with the shortlabels option

\usepackage[shortlabels]{enumitem}

if you have already customized enumerate lists.

Answer 2

You can use enumitem and its align=left

\documentclass{memoir}
\usepackage{enumitem} 
\renewcommand*{\theenumi}{\thesubsection.\arabic{enumi}}
\begin{document}
\chapter{A chapter}
\section{A section}
\subsection{A sub section}
\begin{enumerate}[align=left,leftmargin=*]
  \item Some item Some item Some item Some item Some item Some item Some item Some item Some item Some item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
\end{enumerate}
Some text here
\end{document}

Remember that memoir class emulates the functions of only enumerate package and for more control, enumitem is recommended. Here is an example of more control with a customized alignment.

\documentclass{memoir}
\usepackage{enumitem} % for \midrule macro
\renewcommand*{\theenumi}{\thesubsection.\arabic{enumi}}
\SetLabelAlign{myleft}{\strut\smash{\parbox[t]{\labelwidth}{\raggedright#1}}}
\begin{document}
\chapter{A chapter}
\section{A section}
\subsection{A sub section}
\begin{enumerate}[align=myleft,labelwidth=1.25cm,leftmargin=\dimexpr\labelwidth+\labelsep,
        itemindent=!]
  \item Some item Some item Some item Some item Some item Some item Some item Some item Some item Some item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
  \item Some item
\end{enumerate}
Some text here
\end{document}