nwcollapse

Collapse a network

Syntax

nwcollapse 
[(stat)]
[netname]
[,
by(varname) 
generate(newnetname) 
options]

Description

This command collapses a network, i.e. it merges network nodes. It works very similar as collapse. With option by(varname) one specifies which nodes should be merged. The rule for collapsing two nodes are specified with stat, by default stat = max (see here for possible values). For example, when nodes A and B are collapsed to node Z, Z inherits all the ties from node A and B. The nodes in the new network are named after the values in varname.

By default, an existing network is replaced, unless option generate(newnetname) is specified.

Examples

This collapses the first and the second node of a random network. The collapsed node will have all ties that the original nodes had.

. nwrandom 20, prob(.1) name(mynet)
. gen att = _n
. replace att = 1 in 2
. nwcollapse mynet, by(att)

Supported network types

Binary: yes. Directed: yes. Weighted: yes - generate()’s own collapse function operates on whatever tie values are present. Signed: not checked. Two-mode: not supported - the row-grouping this command performs has no notion of mode, so it would freely collapse mode-1 and mode-2 nodes together; rejected explicitly with a clear error instead.

See also

• collapse
• last certified : 24 Aug 2026