[Tex/LaTex] extra line in table latex

tables

I want to make a table in LaTeX and I wrote the following program:

\documentclass[]{article}
\usepackage{graphicx}
\usepackage{color}
\begin{document}

\begin {center}
\begin {tabular}{| l | l | l | l | l | l |}
\cline{2-6}
& \multicolumn{5}{ |c| }{$\eta_{\infty}$} \\  \cline{2-6}  
&  i=1,f=6 & i=1,f=3 & i=3,f=5& i=4,f=2& i=6,f=3 \\ \hline
$k,l=0,0$  & \textcolor{blue}{0.1811} & \textcolor{blue}{0.1811}&       \textcolor{blue}{0.1811}& \textcolor{blue}{0.1811}& \textcolor{blue}{0.1811} \\ \hline
$k,l=1,2$  &0.3788 &0.3788 &0.2898 &0.2220 &0.2898 \\ \hline
$k,l=1,3$  &0.3788 &\textcolor{red}{0.9393} &0.2898 &0.2898 &0.2220  \\ \hline
$k,l=1,4$  &0.3788 &0.3788 &0.2898 &0.3788 &0.2898  \\ \hline
$k,l=1,5$  &0.3788 &0.3788 &0.2220 &0.2898 &0.2898 \\ \hline
$k,l=1,6$  &\textcolor{red}{0.9393} &0.3788 &0.2898 &0.2898 &0.3788 \\ \hline
$k,l=2,3$  &0.2898 &0.2220 &0.3788 &0.2220 &0.2220 \\ \hline
$k,l=2,4$  &0.2898 &0.2898 &0.2898 &\textcolor{red}{0.9393} &0.2898 \\ \hline
$k,l=2,5$  &0.2898 &0.2898 &0.2220 &0.2220 &0.2898 \\ \hline
$k,l=2,6$  &0.2220 &0.2898 &0.2898 &0.2220 &0.3788\\ \hline
$k,l=3,4$  &0.2898 &0.2220 &0.3788 &0.3788 &0.2220  \\ \hline
$k,l=3,5$  &0.2898 &0.2220 &\textcolor{red}{0.9393} &0.2898 &0.2220  \\ \hline
$k,l=3,6$  &0.2220 &0.2220 &0.3788 &0.2898 &\textcolor{red}{0.9393}  \\ \hline
$k,l=4,5$  &0.2898 &0.2898 &0.2220 &0.3788 &0.2898  \\ \hline
$k,l=4,6$  &0.2220 &0.2898 &0.2898 &0.3788 &0.3788 \\ \hline
$k,l=5,6$  &0.2220 &0.2898 &0.2220 &0.2898 &0.3788  \\ \hline

\end {tabular}\\ 
 Table 2: System efficiency for different k,l and i,f.
\end {center}
\end{document}

Some of the cells have an extra vertical line in the first column, how can I omit it?
Thank you for your soon answering!

Best Answer

enter image description here

\documentclass[]{article}
\usepackage{graphicx}
\usepackage{color}
\begin{document}

\begin {table}\centering
\begin {tabular}{| l | l | l | l | l | l |}
\cline{2-6}
\multicolumn{1}{c|}{}&\multicolumn{5}{c| }{$\eta_{\infty}$} \\  \cline{2-6}  
\multicolumn{1}{c|}{}&  i=1,f=6 & i=1,f=3 & i=3,f=5& i=4,f=2& i=6,f=3 \\ \hline
$k,l=0,0$  & \textcolor{blue}{0.1811} & \textcolor{blue}{0.1811}&       \textcolor{blue}{0.1811}& \textcolor{blue}{0.1811}& \textcolor{blue}{0.1811} \\ \hline
$k,l=1,2$  &0.3788 &0.3788 &0.2898 &0.2220 &0.2898 \\ \hline
$k,l=1,3$  &0.3788 &\textcolor{red}{0.9393} &0.2898 &0.2898 &0.2220  \\ \hline
$k,l=1,4$  &0.3788 &0.3788 &0.2898 &0.3788 &0.2898  \\ \hline
$k,l=1,5$  &0.3788 &0.3788 &0.2220 &0.2898 &0.2898 \\ \hline
$k,l=1,6$  &\textcolor{red}{0.9393} &0.3788 &0.2898 &0.2898 &0.3788 \\ \hline
$k,l=2,3$  &0.2898 &0.2220 &0.3788 &0.2220 &0.2220 \\ \hline
$k,l=2,4$  &0.2898 &0.2898 &0.2898 &\textcolor{red}{0.9393} &0.2898 \\ \hline
$k,l=2,5$  &0.2898 &0.2898 &0.2220 &0.2220 &0.2898 \\ \hline
$k,l=2,6$  &0.2220 &0.2898 &0.2898 &0.2220 &0.3788\\ \hline
$k,l=3,4$  &0.2898 &0.2220 &0.3788 &0.3788 &0.2220  \\ \hline
$k,l=3,5$  &0.2898 &0.2220 &\textcolor{red}{0.9393} &0.2898 &0.2220  \\ \hline
$k,l=3,6$  &0.2220 &0.2220 &0.3788 &0.2898 &\textcolor{red}{0.9393}  \\ \hline
$k,l=4,5$  &0.2898 &0.2898 &0.2220 &0.3788 &0.2898  \\ \hline
$k,l=4,6$  &0.2220 &0.2898 &0.2898 &0.3788 &0.3788 \\ \hline
$k,l=5,6$  &0.2220 &0.2898 &0.2220 &0.2898 &0.3788  \\ \hline
\end {tabular}

\caption{System efficiency for different $k,l$ and $i,f$.}
\end {table}
\end{document}
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