setdiff

Arguments

a, b

vectors, matrices or hypermatrices of real numbers or encoded integers or strings. Both must have the same data types (and integer types).

If the option orien="r" is used, a and b must have the same number of columns. If the orien="c" is used, they must have the same number of rows.

orien

oriented processing:

• "r": rows of a are searched among b ones.
• "c": columns of a are searched among b ones.
• no orien: elements of a are searched among b ones.

v

• sorted vector of a's components that are not in b.
• orien="r": matrix of rows of a that are not in b, sorted in lexicographic order.
• orien="c": matrix of columns of a that are not in b, sorted in lexicographic order.

ka

vector of linear indices of selected a's components, rows, or columns, such that

• v = a(ka), or
• v = a(ka,:) (orien="r"), or
• v = a(:,ka) (orien="c")

Description

setdiff(a, b,..) computes and returns the elements or rows or columns of a that are NOT in b.

All duplicates (elements or rows or columns) are removed from a and from b before processing.

If a is an hypermatrix and the "r" option is used, a is replaced with the matrix of all its rows over all its higher dimensions, before processing. Same thing if b is an hypermatrix. If the "c" option is used, a or/and "b" are replaced with the respective matrices of all their columns.

The format of results is presented in the following table, according to the shape of a and the orien option. In all cases, if all entities of a are in b, [] is returned for v as for ka:

orien →	none		"r"		"c"
a ↓	v	ka	v	ka	v	ka
row	row	row	row	scal	row	row
column	col	col	col	col	col	scal
matrix	col	col	mat	col	mat	row
hypermatrix	col	col	mat	col	mat	row
scalar	scal	scal	scal	scal	scal	scal

v and ka become empty [] if a is empty (whatever is b), or if all a elements are in b.

Examples

Example #1:

a = grand(1, 10,"uin", 0, 9) b = grand(2, 4, "uin", 0, 9) [d, k] = setdiff(a, b); d, k

--> a = grand(1, 10,"uin", 0, 9)
 a  =
   2.   2.   4.   5.   4.   1.   9.   5.   8.   3.

--> b = grand(2, 4, "uin", 0, 9)
 b  =
   5.   0.   9.   9.
   5.   6.   0.   4.

--> [d, k] = setdiff(a, b);
--> d, k
 d  =
   1.   2.   3.   8.

 k  =
   6.   1.   10.   9.
 

Example #2: column-wise processing

a = grand(2, 7,"uin", 0, 3) b = grand(2, 10, "uin", 0, 3) [d, k] = setdiff(a, b, "c"); d, k

--> a = grand(2, 7,"uin", 0, 3)
 a  =
   0.   1.   0.   2.   3.   0.   2.
   2.   2.   2.   1.   0.   1.   2.

--> b = grand(2, 10, "uin", 0, 3)
 b  =
   1.   1.   3.   1.   1.   1.   3.   0.   2.   0.
   3.   3.   2.   2.   0.   0.   1.   0.   1.   0.

--> [d, k] = setdiff(a, b, "c");
--> d, k
 d  =
   0.   0.   2.   3.
   1.   2.   2.   0.

 k  =
   6.   1.   7.   5.
 

Example #3: with some text

v1 = tokens("ab ca ba bb ca cb ba aa cc bc ac aa")' v2 = tokens("cc ac ca bb ac bc ab")' [r, k] = setdiff(v1, v2); r, k

--> v1 = tokens("ab  ca  ba  bb  ca  cb  ba  aa  cc  bc  ac  aa")'
 v1  =
!ab  ca  ac  bb  ca  cb  ba  aa  cc  bc  ac  aa  !

--> v2 = tokens("cc  ac  ca  bb  ac  bc  ab")'
 v2  =
!cc  ac  ca  bb  ac  bc  ab  !

--> [r, k] = setdiff(v1, v2);
--> r, k
 r  =
!aa  ba  cb  !

 k  =
   8.   3.   6.

See also

• unique — ベクトルまたは行列のユニークなな要素を展開
• union — ベクトルの和集合要素を展開
• members — 配列の各要素または他の配列の行または列を数える(及び位置を調べる)
• vectorfind — ベクトルに一致する行列の行または列を見つける

History