# is_weighted

From igraph v1.0.1
by Gabor Csardi

##### Weighted graphs

In weighted graphs, a real number is assigned to each (directed or undirected) edge.

- Keywords
- graphs

##### Usage

`is_weighted(graph)`

##### Arguments

- graph
The input graph.

##### Details

In igraph edge weights are represented via an edge attribute, called
‘weight’. The `is_weighted`

function only checks that such an
attribute exists. (It does not even checks that it is a numeric edge
attribute.)

Edge weights are used for different purposes by the different functions. E.g. shortest path functions use it as the cost of the path; community finding methods use it as the strength of the relationship between two vertices, etc. Check the manual pages of the functions working with weighted graphs for details.

##### Value

A logical scalar.

##### Examples

```
# NOT RUN {
g <- make_ring(10)
shortest_paths(g, 8, 2)
E(g)$weight <- seq_len(ecount(g))
shortest_paths(g, 8, 2)
# }
```

*Documentation reproduced from package igraph, version 1.0.1, License: GPL (>= 2)*

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