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Controlling Command Window Input and Output

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The format Function Suppressing Output Entering Long Statements Command Line Editing

The format Function

The format function controls the numeric format of the values displayed. The function affects only how numbers are displayed, not how MATLAB software computes or saves them. Here are the different formats, together with the resulting output produced from a vector x with components of different magnitudes.

Note   To ensure proper spacing, use a fixed-width font, such as Courier.

x = [4/3 1.2345e-6]

format short

   1.3333    0.0000

format short e

   1.3333e+000  1.2345e-006

format short g

   1.3333  1.2345e-006

format long

   1.33333333333333   0.00000123450000

format long e

   1.333333333333333e+000    1.234500000000000e-006

format long g

   1.33333333333333               1.2345e-006

format bank

   1.33          0.00

format rat

   4/3          1/810045

format hex
 
   3ff5555555555555   3eb4b6231abfd271

If the largest element of a matrix is larger than 10³ or smaller than 10^-3, MATLAB applies a common scale factor for the short and long formats.

In addition to the format functions shown above

format compact

suppresses many of the blank lines that appear in the output. This lets you view more information on a screen or window. If you want more control over the output format, use the sprintf and fprintf functions.

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Suppressing Output

If you simply type a statement and press Return or Enter, MATLAB automatically displays the results on screen. However, if you end the line with a semicolon, MATLAB performs the computation but does not display any output. This is particularly useful when you generate large matrices. For example,

A = magic(100);

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Entering Long Statements

If a statement does not fit on one line, use an ellipsis (three periods), ..., followed by Return or Enter to indicate that the statement continues on the next line. For example,

s = 1 -1/2 + 1/3 -1/4 + 1/5 - 1/6 + 1/7 ...
      - 1/8 + 1/9 - 1/10 + 1/11 - 1/12;

Blank spaces around the =, +, and - signs are optional, but they improve readability.

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Command Line Editing

Various arrow and control keys on your keyboard allow you to recall, edit, and reuse statements you have typed earlier. For example, suppose you mistakenly enter

rho = (1 + sqt(5))/2

You have misspelled sqrt. MATLAB responds with

Undefined function or variable 'sqt'.

Instead of retyping the entire line, simply press the key. The statement you typed is redisplayed. Use the key to move the cursor over and insert the missing r. Repeated use of the key recalls earlier lines. Typing a few characters and then the key finds a previous line that begins with those characters. You can also copy previously executed statements from the Command History. For more information, see Command History.

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More About Matrices and Arrays

Graphics

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