minus - Subtraction - MATLAB (original) (raw)

Syntax

Description

C = [A](#btx9ad2-A) - [B](#btx9ad2-A) subtracts array B from array A by subtracting corresponding elements. The sizes of A andB must be the same or be compatible.

If the sizes of A and B are compatible, then the two arrays implicitly expand to match each other. For example, ifA 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 = minus([A](#btx9ad2-A),[B](#btx9ad2-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 subtract a scalar value from it.

A = [2 1; 3 5]; C = A - 2

The scalar is subtracted from each entry of A.

Create two arrays, A and B, and subtract the second, B, from the first, A.

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

The elements of B are subtracted from the corresponding elements of A.

Use the syntax -C to negate the elements of C.

Create a 1-by-2 row vector and 3-by-1 column vector and subtract 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 a matrix, A. Scale the elements in each column by subtracting the mean.

ans = 2×3

-0.5000 1.0000 -2.5000 0.5000 -1.0000 2.5000

Since R2023a

Create two tables and subtract one of them from the other. 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     0    1 
R2    -1    0 

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.

• 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.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | logical | char | datetime | duration | calendarDuration | table | timetable
Complex Number Support: Yes

Extended Capabilities

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

The minus 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 minus 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, minus supports implicit expansion when the arguments are calendarDuration, datetime, orduration arrays. Between R2020a and R2016b, implicit expansion was supported only for numeric 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.