- mapping-xor mapping1 mapping2procedure
Return a newly allocated mapping whose set of associations is the union, intersection, asymmetric difference, or symmetric difference of the sets of associations of the mappings mappings. Asymmetric difference is extended to more than two mappings by taking the difference between the first mapping and the union of the others. Symmetric difference is not extended beyond two mappings. When comparing associations, only the keys are compared. In case of duplicate keys (in the sense of the mappings comparators), associations in the result mapping are drawn from the first mapping in which they appear.