table too wide for twocolumn-mode document

Question

I have a table which comes outside the text column width into the margin of the paper. How do I make the text in the table align to left ?

 \documentclass[a4paper,10pt]{article}
 \usepackage[utf8]{inputenc}

 \title{}
\author{}

\begin{document}

\maketitle

 \begin{abstract}
 abc
\end{abstract}

\section{table}
\begin{table}[h!]
\caption{Top 5 movies recommended by content-based CF algorithm} %title of the table
\centering
% centering table
\begin{tabular}{c r}
% creating eight columns
\hline\hline
%inserting double-line
Movies&\multicolumn{1}{c}{Genre} \\ [0.5ex]
\hline
% inserts single-line
The Flintstones(1994)
& Children's,Comedy\\
% Entering row contents
Son in Law(1974) & Comedy, Horror\\
The Princess Bride(1987) & Action, Adventure, Comedy, Romance\\
Star Wars(1977) & Action, Adventure, Romance, Sci-Fi, War\\
Toy Story(1995)
& Animated, Animated Children's, Comedy\\[1ex] % [1ex] adds vertical space
\hline
% inserts single-line
\end{tabular}
\label{tab:hresult}
\end{table}
 \end{document}


 This is how it looks : 

Answer 1

Since you use two-column mode, you should use a table* rather than a table environment. The table* environment spans both columns. A restriction is that these floats can only appear at the top of a page.

By the way, I suggest you use the commands \toprule, \midrule, and \bottomrule of the booktabs package in the tabular environment, rather than \hline and various ad-hoc vertical spacing commands. The following modified form of your MWE shows how these commands may be used.

\documentclass[a4paper,10pt,twocolumn]{article}
\usepackage[utf8]{inputenc}
\usepackage{booktabs,lipsum}
\begin{document}
\lipsum[1-5] % filler text
\begin{table*}
\caption{Top 5 movies recommended by content-based CF algorithm} \label{tab:hresult}
\centering
\begin{tabular}{@{}ll@{}}
\toprule
Movies & Genre \\ 
\midrule
The Flintstones (1994) & Children's, Comedy\\
Son in Law (1974) & Comedy, Horror\\
The Princess Bride (1987) & Action, Adventure, Comedy, Romance\\
Star Wars (1977) & Action, Adventure, Romance, Sci-Fi, War\\
Toy Story (1995) & Animated, Animated Children's, Comedy\\
\bottomrule
\end{tabular}
\end{table*}
\lipsum[6-14] % more filler text
\end{document}

Answer 2

Here are a bunch of different options for your table:

1. Your original table with \centering.
2. With \noindent (which aligns it with the left margin), and column specification of {@{}c r@{}} which remove the column padding before the first column and after the last column.
3. All column spacing removed with {@{}c@{}r@{}}, just to see the effect (probably not a good idea).
4. Using {@{}c P{1.5in}@{}} which removed the column spacing as per 2, but also uses the p column type for the second column to allow for paragraph wrapping.

Notes:

• The showframe package was used just to show the page margins.

Code:

\documentclass[a4paper,10pt]{article}
\usepackage[utf8]{inputenc}
\usepackage{array}
\usepackage{showframe}

\newcolumntype{P}[1]{>{\raggedright\arraybackslash}p{#1}<{}}%


\newcommand*{\MyTabular}[1]{%
\begin{tabular}{#1}
% creating eight columns
\hline\hline
%inserting double-line
Movies&\multicolumn{1}{c}{Genre} \\ [0.5ex]
\hline
% inserts single-line
The Flintstones(1994)
& Children's, Comedy\\
% Entering row contents
Son in Law(1974) & Comedy, Horror\\
The Princess Bride(1987) & Action, Adventure, Comedy, Romance\\
Star Wars(1977) & Action, Adventure, Romance, Sci-Fi, War\\
Toy Story(1995)
& Animated, Animated Children's, Comedy\\[1ex] % [1ex] adds vertical space
\hline % inserts single-line
\end{tabular}
}%

\begin{document}

\begin{table}[h!]% Keep effect of \centering localized
\centering 
\MyTabular{c r}
\end{table}


\begin{table}[h!]
\noindent % 
\MyTabular{@{}c r@{}}
\end{table}

\begin{table}[h!]
\noindent % 
\MyTabular{@{}c@{}r@{}}
\end{table}

\begin{table}[h!]
\noindent % 
\MyTabular{@{}c P{1.5in}@{}}
\end{table}
\end{document}