nwreplace
Replace a network
Syntax
nwreplace
netname[subnet]
=netexp
[ifego]
[ifalter]
[if]
Description
Replaces a whole network, a subnetwork or specific tie values with a network expression. This command is the network version of replace. A network expression is very similar to a normal expression in Stata, but it also accepts netnames.
One can also replace tie values in networks by 1) loading a network as Stata variables (see nwload), 2) changing the Stata variables (see replace) and 3) syncing Stata variables and network afterwards (see nwsync). However, replacing the networks directly (as shown below) is the faster and preferred method.
One can also change the entire adjaceny matrix of a network with an existing Mata matrix using nwreplacemat.
Supported network types
Binary: yes. Directed: yes - a replaced value is written to the exact (ego,alter) cell addressed, respecting direction. Weighted: yes, natively - this command’s entire purpose is writing arbitrary tie values via an expression. Signed: yes, any value including negative can be assigned. Two-mode: same as for the bipartite graph read as a one-mode network (valid; no mode-specific normalisation).
Undirected networks - important: a bracket write such as nwreplace mynet[2,1] = 55 addresses EXACTLY the (2,1) cell - it does NOT also write the mirror (1,2) cell, even though mynet is declared undirected. Writing only one side of a pair can leave the network’s own stored matrix genuinely asymmetric while it still reports directed: false (this is deliberate - nwreplace never forces symmetry on your behalf, the same way nwreplacemat’s own underlying set_edge() never does either). If you want a symmetric edit, write both cells explicitly (nwreplace mynet[2,1] = 55 then nwreplace mynet[1,2] = 55), or use nwreplacemat/nwsym to replace or symmetrize the whole matrix at once. Most analysis commands read an undirected network through an accessor that symmetrizes on the fly (taking the max of both directions) and so never notice a one-sided asymmetry left this way - but any command working directly off the network’s own stored ties (rather than through that accessor) will see the asymmetry exactly as written.
Stored results
Scalars
- r(symmetric) 1 if the network’s updated adjacency matrix is symmetric, 0 otherwise
- r(valued) 1 if the network is valued, 0 otherwise
See also
nwcommands version 3.17.6, 9 November 2026 (check your installed version)