Is there a built-in function to concatenate arrays in the third direction?

HORZCAT Horizontal concatenation. [A B] is the horizontal concatenation of matrices A and B. A and B must have the same number of rows. [A,B] is the same thing. Any number of matrices can be concatenated within one pair of brackets. Horizontal and vertical concatenation can be combined together as in [1 2;3 4]. [A B; C] is allowed if the number of rows of A equals the number of rows of B and the number of columns of A plus the number of columns of B equals the number of columns of C. The matrices in a concatenation expression can themselves by formed via a concatenation as in [A B;[C D]]. These rules generalize in a hopefully obvious way to allow fairly complicated constructions. N-D arrays are concatenated along the second dimension. The first and remaining dimensions must match. C = HORZCAT(A,B) is called for the syntax '[A B]' when A or B is an object. Y = HORZCAT(X1,X2,X3,...) is called for the syntax '[X1 X2 X3 ...]' when any of X1, X2, X3, etc. is an object. See also VERTCAT, CAT. Documentation for horzcat doc horzcat Other uses of horzcat Bluetooth/horzcat categorical/horzcat codistributed/horzcat dataset/horzcat datetime/horzcat dlarray/horzcat double/horzcat duration/horzcat fittype/horzcat gpib/horzcat gpuArray/horzcat i2c/horzcat icdevice/horzcat icgroup/horzcat icsignal/horzcat iddata/horzcat inline/horzcat iviconfigurationstore/horzcat laurentPolynomial/horzcat laurpoly/horzcat matlab.mixin.Heterogeneous/horzcat matlab.mixin.indexing.RedefinesParen/horzcat opcroot/horzcat RandStream/horzcat sensingDictionary/horzcat serial/horzcat sym/horzcat symbolic/horzcat tabular/horzcat tall/horzcat tcpip/horzcat tokenizedDocument/horzcat tscollection/horzcat udp/horzcat videoinput/horzcat visa/horzcat

CAT Concatenate arrays. CAT(DIM,A,B) concatenates the arrays A and B along the dimension DIM. CAT(2,A,B) is the same as [A,B]. CAT(1,A,B) is the same as [A;B]. B = CAT(DIM,A1,A2,A3,A4,...) concatenates the input arrays A1, A2, etc. along the dimension DIM. When used with comma separated list syntax, CAT(DIM,C{:}) or CAT(DIM,C.FIELD) is a convenient way to concatenate a cell or structure array containing numeric matrices into a single matrix. Examples: a = magic(3); b = pascal(3); c = cat(4,a,b) produces a 3-by-3-by-1-by-2 result and s = {a b}; for i=1:length(s), siz{i} = size(s{i}); end sizes = cat(1,siz{:}) produces a 2-by-2 array of size vectors. See also NUM2CELL. Documentation for cat doc cat Other uses of cat calendarDuration/cat gpuArray/cat categorical/cat inline/cat codistributed/cat InputOutputModel/cat dataset/cat matlab.mixin.Heterogeneous/cat datetime/cat matlab.mixin.indexing.RedefinesParen/cat dlarray/cat RandStream/cat double/cat sym/cat duration/cat tabular/cat fittype/cat tall/cat geopoint/cat tokenizedDocument/cat