plus - Add numbers, append strings - MATLAB (original) (raw)

Add numbers, append strings

Syntax

Description

C = [A](#btx03j8-1-A) + [B](#btx03j8-1-A) adds arrays A and B by adding corresponding elements. If one input is a string array, then plus appends the corresponding elements as strings.

The sizes of A and B must be the same or becompatible. If the sizes ofA and B are compatible, then the two arrays implicitly expand to match each other. For example, if one ofA or B is a scalar, then the scalar is combined with each element of the other array. Also, vectors with different orientations (one row vector and one column vector) implicitly expand to form a matrix.

example

C = plus([A](#btx03j8-1-A),[B](#btx03j8-1-A)) is an alternate way to execute A + B, but is rarely used. It enables operator overloading for classes.

Examples

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Create an array, A, and add a scalar value to it.

A = [0 1; 1 0]; C = A + 2

The scalar value is added to each entry of A.

Create two 1-by-3 string arrays, then append similarly located strings in the arrays.

s1 = ["Red" "Blue" "Green"]

s1 = 1×3 string "Red" "Blue" "Green"

s2 = ["Truck" "Sky" "Tree"]

s2 = 1×3 string "Truck" "Sky" "Tree"

s = 1×3 string "RedTruck" "BlueSky" "GreenTree"

Create two arrays, A and B, and add them together.

A = [1 0; 2 4]; B = [5 9; 2 1]; C = A + B

The elements of A are added to the corresponding elements of B.

Create a 1-by-2 row vector and 3-by-1 column vector and add them.

a = 1:2; b = (1:3)'; a + b

The result is a 3-by-2 matrix, where each (i,j) element in the matrix is equal to a(j) + b(i):

a=[a1 a2], b=[b1b2b3], a+ b=[a1+ b1a2+ b1a1+ b2a2+ b2a1+ b3a2+ b3].

Create an array, A, and add a column vector to it. The vector is treated as though it is a matrix of the same size as A, so that each element in the vector is added to a row in A.

ans = 2×3

11    12    13

104 105 106

Since R2023a

Create two tables and add them. The row names (if present in both) and variable names must be the same, but do not need to be in the same orders. Rows and variables of the output are in the same orders as the first input.

A = table([1;2],[3;4],VariableNames=["V1","V2"],RowNames=["R1","R2"])

A=2×2 table V1 V2 __ __

R1    1     3 
R2    2     4

B = table([4;2],[3;1],VariableNames=["V2","V1"],RowNames=["R2","R1"])

B=2×2 table V2 V1 __ __

R2    4     3 
R1    2     1

C=2×2 table V1 V2 __ __

R1    2     5 
R2    5     8

Input Arguments

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Operands, specified as scalars, vectors, matrices, multidimensional arrays, tables, or timetables. Inputs A andB must either be the same size or have sizes that are compatible (for example, A is anM-by-N matrix andB is a scalar or1-by-N row vector). For more information, see Compatible Array Sizes for Basic Operations.

If one input is a string array, then the other input can be numeric, character, string, or a cell array. In this case,plus converts the non-string input into a string array and then appends corresponding elements of the inputs.
Operands with an integer data type cannot be complex.
If one input is a datetime array,duration array, orcalendarDuration array, then numeric values in the other input are treated as a number of 24-hour days.

Inputs that are tables or timetables must meet the following conditions: (since R2023a)

If an input is a table or timetable, then all its variables must have data types that support the operation.
If only one input is a table or timetable, then the other input must be a numeric or logical array.
If both inputs are tables or timetables, then:
- Both inputs must have the same size, or one of them must be a one-row table.
- Both inputs must have variables with the same names. However, the variables in each input can be in a different order.
- If both inputs are tables and they both have row names, then their row names must be the same. However, the row names in each input can be in a different order.
- If both inputs are timetables, then their row times must be the same. However, the row times in each input can be in a different order.

Tips

For appending text, plus only operates on string arrays. Use the append function to append text in character vectors or cell arrays.

Extended Capabilities

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Theplus function fully supports tall arrays. For more information, see Tall Arrays.

Inputs cannot be data type logical.

The plus function fully supports GPU arrays. To run the function on a GPU, specify the input data as a gpuArray (Parallel Computing Toolbox). For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Version History

Introduced before R2006a

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The plus operator supports operations directly on tables and timetables without indexing to access their variables. All variables must have data types that support the operation. For more information, see Direct Calculations on Tables and Timetables.

Starting in R2020b, plus supports implicit expansion when the arguments are calendarDuration, datetime, orduration arrays. Between R2020a and R2016b, implicit expansion was supported only for numeric and string data types.

Starting in R2016b with the addition of implicit expansion, some combinations of arguments for basic operations that previously returned errors now produce results. For example, you previously could not add a row and a column vector, but those operands are now valid for addition. In other words, an expression like [1 2] + [1; 2] previously returned a size mismatch error, but now it executes.

If your code uses element-wise operators and relies on the errors that MATLAB previously returned for mismatched sizes, particularly within a try/catch block, then your code might no longer catch those errors.

For more information on the required input sizes for basic array operations, see Compatible Array Sizes for Basic Operations.