Matrices into subsets, according to the extraction conditions

 

 Reference from: https: //blog.csdn.net/neweastsun/article/details/79435271

The above description of FIG accurate visual merge functions, to be noted that the package dplyr, union function effect is equivalent to the effect of the second graph, the effect equivalent to the effect of the function intersect a first graph

 

 

If I want to get the light blue area on the map, use setdiff (A, C)

 

 

 

To obtain the blue region, using setdiff (C, A)