# How to delete the space before and after the 'itemize' or 'enumerate'?

My code is shown below.

\textbf{I. Introduction}\\
\hspace*{1em} \textbf {A. Background:}
\begin{itemize}
\setlength{\itemsep}{0pt}
\setlength{\parsep}{0pt}
\setlength{\parskip}{0pt}
\item[1.] The differences between clear vowels and conversational vowels are widely studies.
\begin{itemize}
\item[a.]Vowel Duration: Clear vowels are generally longer than conversational vowels
\item[b.] Dynamic Formant Movement: Clear vowels exhibit greater movement than naturally produced vowels.
\end{itemize}
\end{itemize}


And the result is shown below. I just want to delete the space before and after the item. I have already set the length as 0pt, but it is not working. Is there something wrong with my code? Thank you very much!!

• Load  enumitem and use begin{enumerate}[label=\alph*., nosep] \item ...\end{enumerate}. – Bernard Oct 24 '20 at 18:55

As @Bernard has already suggested in a comment, you may want to load the enumitem package, switch from itemize to enumerate environments, and start up both enumerate environments with the option nosep.

The following screenshot shows the outputs of both your original code and of the code that implements the preceding suggestions.

\documentclass{article}
\usepackage{enumitem}
\setlength\parindent{0pt}
\begin{document}
% Before:
\hrule
\textbf{I. Introduction}

\hspace*{1em}\textbf {A. Background:}
\begin{itemize}
\setlength{\itemsep}{0pt}
\setlength{\parsep}{0pt}
\setlength{\parskip}{0pt}
\item[1.] The differences between clear vowels and conversational
vowels are widely studies.
\begin{itemize}
\item[a.]Vowel Duration: Clear vowels are generally longer than
conversational vowels
\item[b.] Dynamic Formant Movement: Clear vowels exhibit greater
movement than naturally produced vowels.
\end{itemize}
\end{itemize}
\hrule
% After:
\textbf{I. Introduction}

\hspace*{1em}\textbf{A. Background:}
\begin{enumerate}[nosep,label=\arabic*.]
\item The differences between clear vowels and conversational
vowels are widely studies.
\begin{enumerate}[nosep,label=\alph*.]
\item Vowel Duration: Clear vowels are generally longer than
conversational vowels
\item Dynamic Formant Movement: Clear vowels exhibit greater
movement than naturally produced vowels.
\end{enumerate}
\end{enumerate}
\hrule
\end{document}