An indicator is a time-invariant function of an individual's facts that
takes the value 0 or 1. It is the one type that is both a variable (a
\(\{0,1\}\) weight, for which \(E = V\)) and an include (a subset:
TRUE selects all of time, FALSE selects nothing).
Build one from a pronoun expression or a ~ formula. The expression must
not use time .t. A logical result is always a valid indicator; a numeric
result is accepted but is only checked to be \(\{0,1\}\) when evaluated.
logical_value() evaluates the indicator against an individual's facts .i
and returns a logical. Because an indicator is also an include,
period_included() works too, returning all-of-time or the empty interval.
Usage
indicator(expr)
is_indicator(x)
logical_value(x, .i)
# Default S3 method
logical_value(x, .i)
# S3 method for class 'indicator'
logical_value(x, .i)Value
indicator() returns an indicator.
is_indicator() returns a scalar logical.
logical_value() returns a logical.
Examples
male <- indicator(.i$sex == "male")
logical_value(male, .i = list(sex = "male"))
#> [1] TRUE
period_included(male, .i = list(sex = "female")) # empty interval
#> [1] <NA>