Copy ScientificForm as Latex?

Question

I have a matrix

M = {{-2.78787*10^-6, 0, 0}, {0, 0.00074904, 0}, {0, 0, -0.119373}};

which I'm converting into ScientificForm, with 3 digits precision

ScientificForm[M, 3]
(* {{-2.79*10^(-6),0,0}, {0,7.49*10^(-4),0}, {0,0,-1.19*10^(-1)}} *)

I would like to copy this exact form as a $\LaTeX$ code. Unfortunately, copying as $\LaTeX$ yields

$$ \left( \begin{array}{ccc} -\text{2.7878728277032345$\grave{ }$*${}^{\wedge}$-6} & 0 & 0 \\ 0 & 0.00074904 & 0 \\ 0 & 0 & -0.119373 \\ \end{array} \right)$$

instead of the nice ScientificForm.

Answer 1

Use TeXForm instead of "Copy as LaTeX"

TeXForm[ScientificForm[M, 3]]
(* \left(
\begin{array}{ccc}
 -2.79\times 10^{-6} & 0 & 0 \\
 0 & 7.49\times 10^{-4} & 0 \\
 0 & 0 & -1.19\times 10^{-1} \\
\end{array}
\right) *)

which, when rendered in LaTeX, gives

$$ \left( \begin{array}{ccc} -2.79\times 10^{-6} & 0 & 0 \\ 0 & 7.49\times 10^{-4} & 0 \\ 0 & 0 & -1.19\times 10^{-1} \\ \end{array} \right) $$

One problem you may have is if you had your zeros defined numerically, in which case you get ugly trailing decimal places,

M = {{-2.78787*10^-6, 0.0, 0.0}, {0.0, 0.00074904, 0.0}, {0.0, 
     0.0, -0.119373}};
TeXForm[ScientificForm[M, 3]]

$$\left( \begin{array}{ccc} -2.79\times 10^{-6} & 0. & 0. \\ 0. & 7.49\times 10^{-4} & 0. \\ 0. & 0. & -1.19\times 10^{-1} \\ \end{array} \right)$$

A simple application of Chop works in that case: TeXForm[ScientificForm[Chop@M, 3]]. If you have numbers like 1.0 that you would prefer to be 1 then you need to follow Jens's answer here.