nwkeepnodes
Keep nodes of a network
Syntax
nwkeepnodes
[netname],
nodes(nodeid1... or nodelab1...)
[
attributes(varlist)
generate(newnetname)
netonly
xvars]
nwkeepnodes
[netname],
keepmat(matamatrix)
[
attributes(varlist)
generate(newnetname)
netonly
xvars]
nodes(nodeid1...) |
numlist of nodeid’s to be kept |
nodes(nodelab1…) |
List of nodelab’s to be kept |
keepmat(matamatrix) |
Mata nodes x 1 matrix; 0 = drop, 1 = keep |
attributes(varlist) |
Attribute variables that are included in the drop |
generate(newnetname) |
Generates a new network and does not overwrite the original network |
netonly |
Only update the network, but keep the Stata variables as they were |
xvars |
Generate Stata variables for the network |
Description
Keeps nodes of a network. The nodes that are to be kept can be either specifified by their nodeid or by their nodelab in option nodes(). Alternatively, one can also keep nodes based on a mata matrix.
By default, the command overwrites the original network. This cannot be undone. Hence, it is recommended to specify option generate(), which generates a new network instead and keeps the original network as it was.
The command mirrors nwdropnodes.
Keep the first seven nodes of network flomarriage and save it as network flomarriage_reduced:
. nwwebuse florentine, nwclear
. nwkeepnodes flomarriage, nodes(1/7) generate(flomarriage_reduced)
Keep the nodes “medici” and “pucci”:
. nwwebuse florentine, nwclear
. nwkeepnodes flomarriage, nodes(medici pucci)
Alternatively, one can also keep nodes based on a mata matrix. This drops the first node:
. nwwebuse florentine, nwclear
. mata: k = (0\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1)
. nwkeepnodes flomarriage, keepmat(k)
Everything this command does can also be achieved with nwkeep using the if condition. For example, the following command also keeps the first seven nodes:
. nwwebuse florentine, nwclear
. nwkeep flomarriage if _n <= 7
Note the opposite default polarity between the two interfaces: nwkeep leaves Stata dataset rows alone unless clean is specified, while nwkeepnodes rebuilds the Stata dataset by default unless netonly is specified.
Supported network types
Binary: yes. Directed: yes. Weighted: yes. Signed: yes - a purely structural operation, existing ties and their values are untouched for surviving nodes. Two-mode: mode assignments are preserved for surviving nodes.