Shorter way to color indices of a matrix?

Question

I've made a bordermatrix with brackets [] instead of (), now there are these indices on the top and left side. In my case on the top they are u_1,v_1,u_2,v_2 and so on. On the left side they are F_1x,F_1y,F_2x,F_2y. 
Now I would like to have all the "u_i" indices in blue and all the "v_i" indices in green. The same for the left side, all the "F_ix" blue and all the "F_iy" green. 
My solution looks like this and works, but if the matrix has more rows and lines this will be too much code.

bordermatrix{~ & color{blue!80!black}  bf overline {u}_1 
                     & color{green!80!black} bf overline {v}_1 
                     & color{blue!80!black}  bf overline {u}_5 
                     & color{green!80!black} bf overline {v}_5 cr
    color{blue!80!black} bf overline {F}_{1x} & 336000 & 0 & -336000 & 0 cr
    color{green!80!black} bf overline {F}_{1y} & 0 & 0 & 0 & 0 cr
    color{blue!80!black} bf overline {F}_{5x} & -336000 & 0 & 336000 & 0 cr
    color{green!80!black} bf overline {F}_{5y} & 0 & 0 & 0 & 0 cr
              }

Is there a shorter more elegant way to achieve the same result?

Gonzalo Medina · Accepted Answer

Using some commands can do the job easier; the example also includes an example using the blkarray package:

documentclass{article}
usepackage{xcolor}
usepackage{amsmath}
usepackage{blkarray}

newcommandGmat[2]{%
  color{green!80!black}mathbf{overline{#1}_{#2}}}
newcommandBmat[2]{%
  color{blue!80!black}mathbf{overline{#1}_{#2}}}

begin{document}

[
bordermatrix{ 
~ & Bmat{u}{1} & Gmat{v}{1} & Bmat{u}{5} & Gmat{v}{5} cr
Bmat{F}{1x} & 336000 & 0 & -336000 & 0 cr
Gmat{F}{1y} & 0 & 0 & 0 & 0 cr
Bmat{F}{5x} & -336000 & 0 & 336000 & 0 cr
Gmat{F}{5y} & 0 & 0 & 0 & 0 cr
} 
]

[
begin{blockarray}{ccccc}
~ & Bmat{u}{1} & Gmat{v}{1} & Bmat{u}{5} & Gmat{v}{5} 
begin{block}{c[cccc]}
Bmat{F}{1x} & 336000 & 0 & -336000 & 0 
Gmat{F}{1y} & 0 & 0 & 0 & 0 
Bmat{F}{5x} & -336000 & 0 & 336000 & 0 
Gmat{F}{5y} & 0 & 0 & 0 & 0 
end{block}
end{blockarray}
 ]

end{document}

F. Pantigny · Answer

Here is a way to do that with the environments of nicematrix.
documentclass{article}
usepackage{xcolor}
usepackage{amsmath}
usepackage{nicematrix}

begin{document}

newcommandmat[2]{mathbf{overline{#1}_{#2}}}

NiceMatrixOptions
  { 
    code-for-first-row = ifodd value{jCol} color{blue} else color{green} fi ,
    code-for-first-col = ifodd value{iRow} color{blue} else color{green} fi 
  }
[begin{pNiceMatrix}[first-row,first-col]
            & mat{u}{1} & mat{v}{1} & mat{u}{5} & mat{v}{5} 
mat{F}{1x} & 336000     & 0          & -336000    & 0 
mat{F}{1y} & 0          & 0          & 0          & 0 
mat{F}{5x} & -336000    & 0          & 336000     & 0 
mat{F}{5y} & 0          & 0          & 0          & 0 
end{pNiceMatrix}]

[begin{bNiceMatrix}[first-row,first-col]
            & mat{u}{1} & mat{v}{1} & mat{u}{5} & mat{v}{5} 
mat{F}{1x} & 336000     & 0          & -336000    & 0 
mat{F}{1y} & 0          & 0          & 0          & 0 
mat{F}{5x} & -336000    & 0          & 336000     & 0 
mat{F}{5y} & 0          & 0          & 0          & 0 
end{bNiceMatrix}]

end{document}

Shorter way to color indices of a matrix?

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