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Concatenate arrays along specified dimension


C = cat(dim, A, B)
C = cat(dim, A1, A2, A3, A4, ...)


C = cat(dim, A, B) concatenates the arrays A and B along array the dimension specified by dim. The dim argument must be a real, positive, integer value.

C = cat(dim, A1, A2, A3, A4, ...) concatenates all the input arrays (A1, A2, A3, A4, and so on) along array dimension dim.

For nonempty arrays, cat(2, A, B) is the same as [A, B], and cat(1, A, B) is the same as [A; B].

If your input arrays are tables or timetables, dim must be either 1 or 2. cat then concatenates by calling vertcat or horzcat respectively.



A =               B =
     1     2                   5     6
     3     4                   7     8

concatenating along different dimensions produces

The commands

A = magic(3); B = pascal(3);
C = cat(4, A, B);

produce a 3-by-3-by-1-by-2 array.


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.

You can concatenate categorical arrays with cell arrays of character vectors. For more information, see Combine Categorical Arrays.

If all the input arrays are ordinal categorical arrays, they must have the same sets of categories including their order. For more information, see Ordinal Categorical Arrays.

You can concatenate datetime arrays with cell arrays of character vectors.

You can concatenate duration arrays and calendar duration arrays. The result is a calendar duration array.

You can concatenate duration or calendar duration arrays with numeric arrays. Prior to concatenation, MATLAB® converts the numeric array to an array of equivalent days using the days function.

You can concatenate string arrays with numeric arrays, logical arrays, character vectors, or cell arrays. The non-string arrays are first converted to a string array, and the output is returned as a string array.

For information on combining unlike integer types, integers with nonintegers, cell arrays with non-cell arrays, or empty matrices with other elements, see Valid Combinations of Unlike Classes

Extended Capabilities

Introduced before R2006a