setdiff

Class: dataset

(Not Recommended) Set difference for dataset array observations

The dataset data type is not recommended. To work with heterogeneous data, use the MATLAB^® table data type instead. See MATLAB table documentation for more information.

Syntax

C = setdiff(A,B)
C = setdiff(A,B,vars)
C = setxor(A,B,vars,setOrder)
[C,iA] = setxor(___)


Description

C = setdiff(A,B) for dataset arrays A and B returns the set of observations that are in A but not B, with repetitions removed. The observations in the dataset array C are sorted.

C = setdiff(A,B,vars) returns the set of observations that are in A but not B, considering only the variables specified in vars, with repetitions removed. The observations in the dataset array C are sorted by these variables. The values for variables not specified in vars for each observation in C are taken from the corresponding observation in A. If there are multiple observations in A that correspond to an observation in C, those values are taken from the first occurrence.

C = setxor(A,B,vars,setOrder) returns the observations in C in the order specified by setOrder.

[C,iA] = setxor(___) also returns the index vector iA such that C = A(iA,:). If there are repeated observations in A, then setxor returns the index of the first occurrence. You can use any of the previous input arguments.

Input Arguments

A,B	Input dataset arrays.
vars	String array or cell array of character vectors containing variable names, or a vector of integers containing variable column numbers. vars indicates the variables that setdiff considers. Specify vars as [] to use its default value of all variables.
setOrder	Flag indicating the sorting order for the observations in C. The possible values of setOrder are: 'sorted' Observations in C are in sorted order (default). 'stable' Observations in C are in the same order that they appear in A.

Output Arguments

C	Dataset array with the observations that are in A but not B, with repetitions removed. C is in sorted order (by default), or the order specified by setOrder.
iA	Index vector, indicating the observations from A that are in C. The vector iA contains the index to the first occurrence of any repeated observations in A.

Examples

Set Difference of Two Dataset Arrays

Create a scalar structure array, and then convert it into two dataset arrays.

S(1,1).Name = 'CLARK';
S(1,1).Gender = 'M';
S(1,1).SystolicBP = 124;
S(1,1).DiastolicBP = 93;

S(2,1).Name = 'BROWN';
S(2,1).Gender = 'F';
S(2,1).SystolicBP = 122;
S(2,1).DiastolicBP = 80;

S(3,1).Name = 'MARTIN';
S(3,1).Gender = 'M';
S(3,1).SystolicBP = 130;
S(3,1).DiastolicBP = 92;

A = struct2dataset(S(1:2));
B = struct2dataset(S(2:3));

The intersection of A and B is the second observation, with last name BROWN.

Return the set difference of A and B.

[C,iA] = setdiff(A,B)

C = 
    Name             Gender       SystolicBP    DiastolicBP
    {'CLARK'}        {'M'}        124           93         

iA = 1

The first observation in A is not present in B.