cat
stacks vectors matrices or arrays into an hypermatrix or hyperarray
Syntax
y = cat(dim, A1, A2, ...,An)
Arguments
- dim
integer>0: index of the dimension along which input arrays must be stacked.
- A1, A2,..An
scalars, vectors, matrices or hypermatrices of compatible data types, or cells arrays.
A1,A2,...,An
must be of the same sizes, except in the direction #dim
of stacking :size(A1,i)=size(A2,i)=...=size(An,i)
for alli <> dim
.- y
a vector, matrix, hypermatrix, or ND-array of cells or of structures. For all
i <> dim
,size(y,i)==size(A1,i)
, andsize(y,dim) == sum(size(Ai, dim)))
.
Description
y=cat(dim,A1,A2,...,An)
: y
is the result of the
concatenation of the input arguments A1,A2,...,An
, along the
dimension #dim.
cat(1, A1, A2, A3)
is equivalent to [A1 ; A2 ; A3]
.
cat(2, A1, A2, A3)
is equivalent to [A1 A2 A3]
.
Brackets are faster and must be preferred in both cases.
When input arrays have not all the same data type, automatical conversion rules similar
to the [,]
and [;]
ones are applied, as described
in the [brackets] page.
cat()
is useful mainly for dim > 2
, to build an
hypermatrix or hypercell.
Examples
Example #1: Building a vector along dim #3
cat(3, 4, -1, 3)
--> cat(3, 4, -1, 3) ans = (:,:,1) 4. (:,:,2) -1. (:,:,3) 3.
Example #2: Building a matrix of text of size(1,3,2):
cat(3, ["a" "aa" "aaa"], ["b" "bb" "bbb"])
--> cat(3, ["a" "aa" "aaa"], ["b" "bb" "bbb"]) ans = (:,:,1) !a aa aaa ! (:,:,2) !b bb bbb !
Example #3: Stacking separate R G B layers of a mini RGB image:
R = uint8(grand(2,4,"uin",0,255)) G = uint8(grand(2,4,"uin",0,255)) B = uint8(grand(2,4,"uin",0,255)) cat(3, R, G, B)
--> R = uint8(grand(2,4,"uin",0,255)) R = 142 8 11 234 191 249 252 51 --> G = uint8(grand(2,4,"uin",0,255)) G = 255 246 104 89 152 71 112 17 --> B = uint8(grand(2,4,"uin",0,255)) B = 170 182 39 197 115 108 16 51 --> cat(3, R, G, B) ans = (:,:,1) 142 8 11 234 191 249 252 51 (:,:,2) 255 246 104 89 152 71 112 17 (:,:,3) 170 182 39 197 115 108 16 51
Example #4: Building an hypercell:
--> A1 = {%T "abc" ; (1-%z)^2, %pi} A1 = [1x1 boolean ] [1x1 string ] [1x1 polynomial] [1x1 constant] --> A2 = {%s^2, gda(); %F, list(-5, "hello")} A2 = [1x1 polynomial] [1x1 handle] [1x1 boolean ] [ list ] --> cat(3, A1, A2) ans = (:,:,1) [1x1 boolean ] [1x1 string ] [1x1 polynomial] [1x1 constant] (:,:,2) [1x1 polynomial] [1x1 handle] [1x1 boolean ] [ list ]
See also
- brackets [..] — Concaténation. Récipients d'une affectation. Résultats d'une function
- lstcat — concaténation de listes
- permute — permute les dimensions d'un tableau à N dimensions
- matrix — redimensionne un tableau, à nombre et ordre inchangés des éléments
History
Version | Description |
2023.1 | Arrays of compatible types accepted, according to [,] and [;] transtyping rules. |
Report an issue | ||
<< is<forme> | Matrice - façonnage | circshift >> |