input

Request user input

Syntax

Description

example

result = input(prompt) requests user input by displaying the prompt string on the screen. MATLAB® waits for input from the keyboard, evaluates any expressions in the input, and then returns the result. To evaluate expressions, the input function can use variables in the current workspace.

  • If you press the Return key without entering anything, then input returns an empty matrix.

  • If you enter an invalid expression at the prompt, then MATLAB displays the relevant error message, and then redisplays the prompt.

example

str = input(prompt,'s') returns the entered text as a string, without evaluating expressions.

Examples

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Request Numeric Input or Expression

Request a numeric input, and then multiply the input by 10.

prompt = 'What is the original value? ';
result = input(prompt)
X = result*10

At the prompt, enter a numeric value or array, such as 42.

result =
    42

X =
   420

The input function also accepts expressions. For example, rerun the code.

prompt = 'What is the original value? ';
result = input(prompt)
X = result*10

At the prompt, enter magic(3).

result =
     8     1     6
     3     5     7
     4     9     2

X =
    80    10    60
    30    50    70
    40    90    20

The expression does not need to return a numeric result. For example:

prompt = 'What color is the sun? ';
result = input(prompt)

At the prompt, type upper('yellow').

result =
YELLOW

Request Unprocessed Text Input

Request a simple text response that requires no evaluation.

prompt = 'Do you want more? Y/N [Y]: ';
str = input(prompt,'s');
if isempty(str)
    str = 'Y';
end

The input function returns the text exactly as typed. If the input is empty, this code assigns a default value, 'Y', to the output string, str.

Input Arguments

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prompt — Query that requests inputstring

Query that requests input, specified as a string.

To create a prompt that spans several lines, use '\n' to indicate each new line. To include a backslash ('\') in the prompt, use '\\'.

Output Arguments

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result — Result calculated from inputarray

Result calculated from input, returned as an array. The type and dimensions of the array depend upon the response to the prompt.

str — Exact text of inputstring

Exact text of the input, returned as a string.

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