Measure to compare two or more sets w.r.t. their similarity. For two sets \(A\) and \(B\), it is defined as $$ J(A, B) = \frac{|A \cap B|}{|A \cup B|}. $$ If more than two sets are provided, the mean of all pairwise scores is calculated.

This measure is undefined if two or more sets are empty.

This measure requires learners with property `"selected_features"`

.
The extracted feature sets are passed to `mlr3measures::jaccard()`

from
package mlr3measures.

If the measure is undefined for the input, `NaN`

is returned.
This can be customized by setting the field `na_value`

.

This Measure can be instantiated via the dictionary mlr_measures or with the associated sugar function `msr()`

:

mlr_measures$get("sim.jaccard") msr("sim.jaccard")

Type:

`"similarity"`

Range: \([0, 1]\)

Minimize:

`FALSE`

Dictionary of Measures: mlr_measures

`as.data.table(mlr_measures)`

for a complete table of all (also dynamically created) Measure implementations.

Other similarity measures:
`mlr_measures_sim.phi`