Some additional utilities that are useful when processing CSV headers and data.
Calculate the intersection between two string slices. The first returned slice is the intersection between the two slices. The second returned slice is a slice of elements in the first slice but not the second. The third returned slice is a slice of elements in the second slice but not the first.
Return a map that maps each string in the input slice to its index in the slice.
Answer true if the index contains the specified string.