setdiff函數是什么？

set difference.

C=setdiff(A,B) for vector A and B, return the values in A that are not in B with no repetitions. C will be sorted.

對于向量A,向量B，C=setdiff(A,B)函數返回在向量A中卻不在向量B中的元素，并且C中不包含重復元素，并且從小到大排序。

[C,IA] = setdiff(A,B) also returns an index vector IA such that C = A(IA). If there are repeated values in A that are not in B, then the index of the first occurrence of each repeated value is returned.

返回值C同上，IA是C中元素在向量A中的下標（索引）。如果A中存在重復元素，并且該元素不在B中，就返回重復元素的第一次出現的下標。