vertcat - Concatenate arrays vertically - MATLAB (original) (raw)

Concatenate arrays vertically

Syntax

Description

C = vertcat([A](#mw%5F0d1ace8b-760f-4ca6-976f-43568bd751c6),[B](#mw%5F0448a926-2c04-4000-8031-2fd82861bd71)) concatenates B vertically to the end of A whenA and B have compatible sizes (the lengths of the dimensions match except in the first dimension).

example

C = vertcat([A1,A2,…,An](#mw%5Ff27487d4-a3db-458d-9a84-4e96b59c8652)) concatenatesA1, A2, … , An vertically.

vertcat is equivalent to using square brackets to vertically concatenate or append arrays. For example, [A; B] is the same asvertcat(A,B) when A and B are compatible arrays.

example

Examples

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Concatenate two matrices vertically.

Create two matrices, and vertically append the second matrix to the first by using square bracket notation.

C = 3×3

 1     2     3
 4     5     6
 7     8     9

Now, vertically append the second matrix to the first by using vertcat.

D = 3×3

 1     2     3
 4     5     6
 7     8     9

Create a table A with three rows and five variables.

A = table([5;6;5],['M';'M';'M'],[45;41;40],[45;32;34],{'NY';'CA';'MA'},... 'VariableNames',{'Age' 'Gender' 'Height' 'Weight' 'Birthplace'},... 'RowNames',{'Thomas' 'Gordon' 'Percy'})

A=3×5 table Age Gender Height Weight Birthplace ___ ______ ______ ______ __________

Thomas     5       M         45        45        {'NY'}  
Gordon     6       M         41        32        {'CA'}  
Percy      5       M         40        34        {'MA'}

Create a table B with the same variables as A except for order.

B = table(['F';'M';'F'],[6;6;5],{'AZ';'NH';'CO'},[31;42;33],[39;43;40],... 'VariableNames',{'Gender' 'Age' 'Birthplace' 'Weight' 'Height'})

B=3×5 table Gender Age Birthplace Weight Height ______ ___ __________ ______ ______

  F        6       {'AZ'}        31        39  
  M        6       {'NH'}        42        43  
  F        5       {'CO'}        33        40

Vertically concatenate tables A and B. The variables of C are in the same order as the variables of A and default row names are used for the rows from B.

C=6×5 table Age Gender Height Weight Birthplace ___ ______ ______ ______ __________

Thomas     5       M         45        45        {'NY'}  
Gordon     6       M         41        32        {'CA'}  
Percy      5       M         40        34        {'MA'}  
Row4       6       F         39        31        {'AZ'}  
Row5       6       M         43        42        {'NH'}  
Row6       5       F         40        33        {'CO'}

Concatenate a date character vector, a string date, and a datetime into a single column of dates. The result is a datetime column vector.

chardate = '2016-03-24'; strdate = "2016-04-19"; t = datetime('2016-05-10','InputFormat','yyyy-MM-dd'); C = vertcat(chardate,strdate,t)

C = 3×1 datetime 24-Mar-2016 19-Apr-2016 10-May-2016

Concatenate three string arrays into a single array.

A1 = ["str1" "str2"]; A2 = ["str3" "str4"]; A3 = ["str5" "str6"]; C = vertcat(A1,A2,A3)

C = 3×2 string "str1" "str2" "str3" "str4" "str5" "str6"

Create a cell array containing two matrices. Vertically concatenate the matrices from the cell array into one matrix.

M1 = [1 2; 3 4]; M2 = [5 6; 7 8]; A1 = {M1,M2}; C = vertcat(A1{:})

Input Arguments

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First input, specified as a scalar, vector, matrix, multidimensional array, table, or timetable.

Second input, specified as a scalar, vector, matrix, multidimensional array, table, or timetable.

The elements of B are concatenated to the end of the first input along the first dimension. The sizes of the input arguments must be compatible. For example, if the first input is a matrix of size 3-by-2, thenB must have 2 columns.
All table inputs must have unique row names. If some of the table inputs do not have row names, vertcat fills in default row names for the output. Variable names in each table input must be the same, but the variables can be in a different order. vertcat concatenates by matching variable names. For table inputs, vertcat also concatenatesRowNames property values. Other property values of the output table are assigned using the first nonempty (or nondefault) property values of the corresponding inputs.
Row times of timetable inputs do not need to be unique. Variable names in each timetable input must be the same, but the variables can be in a different order.vertcat concatenates by matching variable names. For timetable inputs, vertcat also concatenates RowTimes property values and events that are attached to the inputs. Other property values of the output timetable are assigned using the first nonempty (or nondefault) property values of the corresponding inputs.
You can concatenate valid combinations of different types. For more information about concatenating character arrays, logical arrays, and numeric types, see Valid Combinations of Unlike Classes.

List of inputs, specified as a comma-separated list of elements to concatenate in the order they are specified.

The inputs must have compatible sizes. For example, if A1 is a row vector of length m, then the remaining inputs must each have m columns to concatenate vertically.
All table inputs must have unique row names. If some of the table inputs do not have row names, vertcat fills in default row names for the output. Variable names in each table input must be the same, but the variables can be in a different order. vertcat concatenates by matching variable names. For table inputs, vertcat also concatenatesRowNames property values. Other property values of the output table are assigned using the first nonempty (or nondefault) property values of the corresponding inputs.
Row times of timetable inputs do not need to be unique. Variable names in each timetable input must be the same, but the variables can be in a different order.vertcat concatenates by matching variable names. For timetable inputs, vertcat also concatenates RowTimes property values and events that are attached to the inputs. Other property values of the output timetable are assigned using the first nonempty (or nondefault) property values of the corresponding inputs.
You can concatenate valid combinations of different types. For more information about concatenating character arrays, logical arrays, and numeric types, see Valid Combinations of Unlike Classes.

Algorithms

When concatenating an empty array to a nonempty array, vertcat omits the empty array in the output. For example, vertcat([1; 2],[]) returns the column vector [1; 2].

If all input arguments are empty and have compatible sizes, thenvertcat returns an empty array whose size is equal to the output size as when the inputs are nonempty. For example, vertcat(zeros(1,0),zeros(2,0)) returns a 3-by-0 empty array. If the input sizes are not compatible, thenvertcat returns a 0-by-0 empty array.

Extended Capabilities

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Thevertcat function supports tall arrays with the following usage notes and limitations:

Vertical concatenation of character arrays is not supported.
Concatenation of ordinal categorical arrays is not supported.
When vertically concatenating two tall arrays, the result is a tall array based on a different datastore than the input tall arrays. Therefore, if you try to combine the result of the concatenation with one of the input tall arrays, the arrays are incompatible. For example, the following command results in an error, since the original tall table T is based on one datastore, and the output of the concatenation operation is based on another datastore:
T.Var3 = [T.Var1(1); T.Var2(2:end)]
Alternatively, if you only concatenate in-memory values to a tall array, then the result of the concatenation is based on the same datastore. For example, if you replaceT.Var1(1) in the previous example with an in-memory scalar, then the command executes:
T.Var3 = [0; T.Var2(2:end)]

For more information, see Tall Arrays.

The vertcat function supports GPU array input with these usage notes and limitations:

Sparse matrices are not supported.

For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Version History

Introduced before R2006a