display

Show information about variable or result of expression

Syntax

display(X)

Description

display(X) is called by MATLAB^® when a statement or expression is not terminated by a semicolon. Omitting the terminating semicolon from a statement or expression displays a result.

MATLAB calls the display function to show information about an intermediate result, such as the values, size, type, and variable name.

To show the value of a variable or to show program output in the command window, use the disp function.

To customize the display of user-defined objects, use the techniques described in the Customize Object Display for Classes topic.

Examples

Unterminated Variable Assignment

MATLAB calls display when you make an assignment to a variable without terminating the statement with a semicolon. In this example, display shows the variable name and the value.

a = 7

a =

     7

Terminated Variable Assignment

MATLAB does not call display when you make an assignment to a variable and the statement is terminated with a semicolon.

a = 7;

Unterminated Expression

When you execute an expression without a semicolon, MATLAB assigns the result to a variable called ans, which the display function shows in the command window.

format long
sqrt(2)

ans =

   1.414213562373095

Input Arguments

X — Result of executing a statement or expression

variable | expression

Result of executing a statement or expression, passed to the display function by MATLAB.

More About

Assignment to ans

Executing an expression without terminating the expression with a semicolon causes the result to be displayed in the command window. MATLAB assigns the result of an expression to a variable named ans when the result is not assigned to a variable explicitly.

4 * 5 - 13

ans =

    7

To display the result in the command window without displaying ans, use the disp function.

disp(4 * 5 - 13)

7

If an expression is terminated by a semicolon, MATLAB does not display a value, but still assigns the result to the ans variable.

4 * 5 - 13;
ans

ans =

     7

Display Results in Command Window

Omitting the terminating semicolon is useful when you want to see intermediate results from statements in a program. For example, compare these two statements by omitting the semicolon. The display function shows the results in the command window.

result1 = 4 * 5 - 13

result1 =

     7

result2 = 4 * (5 - 13)

result2 =

   -32

Information Shown by the display Function

The display function provides information about the kind of values that are the result of executing a statement or expression. This information is useful for understanding how a program or script works.

For example, this statement assigns a uint8 vector of values 1 2 3 4 to the variable named a. The display function shows the variable name, the size and type, and the values.

a = uint8([1 2 3 4])

a =

  1×4 uint8 row vector

   1   2   3   4

For empty values (numeric types, char, struct, and cell) the display function displays:

• [] — for numeric types

• "0x0 struct array with no fields." — for empty structs.

• "0x0 empty cell array" — for empty cell arrays.

• "0x0 empty char array" — for empty char arrays

• "0x0 empty string array" — for empty string arrays

To show the actual values that are the intended output from a program, like text and numbers, call the disp function. The disp function does not display the variable name or ans. Also, disp displays nothing for built-in types (numeric types, char, struct, and cell) when the value is empty.