`nwrecode`

Recode network

Syntax

nwrecode [netlist] (rule) 
[(rule) ...]
[, generate(newnetlist) prefix(str) test]
where the most common forms for rule are
hline 16c TThline 13c TThline 27
c | rule           c | Example     c | Meaning                   c |
hline 16c +hline 13c +hline 27
c | # = #          c | 3 = 1       c | 3 recoded to 1            c |
c | # # = #        c | 2 . = 9     c | 2 and . recoded to 9      c |
c | #/# = #        c | 1/5 = 4     c | 1 through 5 recoded to 4  c |
c | nonm:issing = # c | nonmiss = 8 c | all other nonmissing to 8 c |
c | mis:sing = #    c | miss = 9    c | all other missings to 9   c | 
c | else  = #      c | else = 44   c | all other to 44           c |
hline 16c BThline 13c BThline 27
The keyword rules missing, nonmissing, and else must be the
last rules specified.  else may not be combined with missing or 
nonmissing.

Description

nwrecode changes the dyad values of networks according to the specified rules. It works almost exactly as recode, but for networks. Dyad values that do not meet any of the conditions of the rules are left unchanged, unless an otherwise rule is specified.

min and max provide a convenient way to refer to the minimum and maximum for each dyad value in netlist and may be used in both the from-value and the to-value parts of the specification.

Common recipe: dichotomizing at a single cutoff. A frequent special case is turning a valued network binary at one threshold - values at or above the cutoff become 1, everything else becomes 0:

. nwrecode trade (100/max=1) (min/max=0)

For exactly this case, nwdichotomize is a thin, more directly discoverable wrapper around
the same rule shown above: nwdichotomize trade, threshold(100). Reach for nwrecode
directly whenever you need something nwdichotomize does not offer - multiple bands, an
otherwise rule, or missing/nonmissing handling.

Options

dlgtab:Options

generate(newnetlist) specifies the names of the network(s) that will contain the transformed dyads. into() is a synonym for generate().

If generate() is not specified, the input networks are overwritten; Overwriting networks is dangerous (you cannot undo changes, so we strongly recommend specifying nwgenerate().

prefix(str) specifies that the recoded networks be returned in new networks formed by prefixing the names of the original networks with str.

test specifies that Stata test whether rules are ever invoked or that rules overlap; for example, (1/5=1) (3=2).

Examples

Setup

. nwwebuse gang
. nwwebuse glasgow
List the network adjacency matrix
. nwsummarize gang, mat
For gang, change 1 to 5, leave all other values unchanged, and store
the results in nx
. nwrecode gang (1 = 5), generate(nx)
List the network adjacency matrix
. nwsummarize gang nx, mat
For gang, swap 1 and 2, and store the results in nx1
. nwrecode gang (1 = 2) (2 = 1), generate(nx1)
List the network adjacency matrix
. nwsummarize gang nx1, mat
For gang, collapse 1 and 2 into 1, change 3 through 4
to 2, and store the results in nx2
. nwrecode gang (1 2 = 1) (3/4 = 2), generate(nx2)
List the network adjacency matrix
. nwsummarize gang nx2, mat
For glasgow1, glasgow2, and glasgow3, change dyad values 1 to 99 and store the
transformed networks in new_glasgow1, new_glasgow2, and new_glasgow3.
. nwrecode glasgow1-glasgow3 (1=99) ,

pre(new) test

List the network adjacency matrices
. nwsummarize glasgow1-3 new_glasgow1-3, mat

Supported network types

Binary: yes - recoding a binary network’s 0/1 values is a degenerate but valid case. Directed: yes. Weighted: yes, natively - this command’s entire purpose is recoding tie values via a rule. Signed: yes, a recode rule can map negative values like any other. Two-mode: not checked.

nwrecode