ismember - Array elements that are members of set
Syntax
tf = ismember(A, S)
tf = ismember(A, S, 'rows')
[tf, loc] = ismember(A, S, ...)
Description
tf = ismember(A, S) returns
an array the same size as A, containing logical 1 (true)
where the elements of A are in the set S,
and logical 0 (false) elsewhere.
In set theory terms, k is 1 where A ∊ S.
Inputs A and S can be numeric
or character arrays or cell arrays of strings.
tf = ismember(A, S, 'rows'),
when A and S are matrices with
the same number of columns, returns a vector containing 1 where
the rows of A are also rows of S and 0 otherwise.
You cannot use this syntax if A or S is
a cell array of strings.
[tf, loc] = ismember(A, S, ...) returns
an array loc containing the highest index in S for
each element in A that is a member of S.
For those elements of A that do not occur in S, ismember returns 0.
Remarks
Because NaN is considered to be not equal to anything, it is
never a member of any set.
Examples
set = [0 2 4 6 8 10 12 14 16 18 20];
a = (1:5)'
a =
1
2
3
4
5
ismember(a, set)
ans =
0
1
0
1
0
set = [5 2 4 2 8 10 12 2 16 18 20 3];
[tf, index] = ismember(a, set);
index
index =
0
8
12
3
1See Also
issorted, intersect, setdiff, setxor, union, unique, is*
 | ismac | | ismethod |  |
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