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networks[head] - find the head of a directed edge
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Calling Sequence
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head(G)
head(e, G)
head(eset, G)
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Parameters
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G
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graph or network
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e
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edge of G
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eset
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set or list of edges of G
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Description
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If a single argument G is passed then a table is returned.
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If a single edge e is passed the either the head of e or NULL is returned depending on whether or not e is directed.
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If a set of edges eset is passed then a set or list of head vertices is returned.
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This routine is normally loaded via the command with(networks) but may also be referenced using the full name networks[head](...).
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Examples
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Important:The networks package has been deprecated. Use the superseding pakcage GraphTheoryinstead.
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![addedge([[1, 2], [2, 3], [3, 4], [4, 5]], G)](/support/helpjp/helpview.aspx?si=8229/file07421/math133.png)
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![TABLE([e4 = 5, e3 = 4, e2 = 3, e1 = 2])](/support/helpjp/helpview.aspx?si=8229/file07421/math154.png)
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![head([e1, e2, e5], G)](/support/helpjp/helpview.aspx?si=8229/file07421/math158.png)
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![[2, 3]](/support/helpjp/helpview.aspx?si=8229/file07421/math161.png)
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