SetEdgeWeight is used to change the weight of an edge of a weighted graph. It returns the old weight of the edge.

GetEdgeWeight is used to get the weight of an edge of a weighted graph.

$\mathrm{with}\left(\mathrm{GraphTheory}\right)\:$

$G≔\mathrm{MakeWeighted}\left(\mathrm{CompleteGraph}\left(4\right)\right)$

$G≔\mathrm{Graph\; 1:\; an\; undirected\; weighted\; graph\; with\; 4\; vertices\; and\; 6\; edge(s)}$

$\mathrm{GetEdgeWeight}\left(G\,\left\{1\,2\right\}\right)$

$1$

$\mathrm{SetEdgeWeight}\left(G\,\left\{1\,2\right\}\,3\right)$

$1$

$\mathrm{GetEdgeWeight}\left(G\,\left\{1\,2\right\}\right)$

$3$

$$\begin{gathered} \mathbf{for}e\mathbf{in}\mathrm{Edges}\left(\mathrm{CycleGraph}\left(4\right)\right)\mathbf{do} \\ \mathrm{SetEdgeWeight}\left(G\,e\,2\right) \\ \mathbf{end}\mathbf{do} \end{gathered}$$

$1$

$\mathrm{WeightMatrix}\left(G\right)$

$\left[\begin{array}{cccc}0& 2& 1& 2\\ 2& 0& 2& 1\\ 1& 2& 0& 2\\ 2& 1& 2& 0\end{array}\right]$