Display without new line

To demonstrate various formats of MATLAB, I use the following script:

x = 1/7;
format short, fprintf(['format short: ']), x % default
format short e, fprintf(['format short e: ']), x
format short g, fprintf(['format short g: ']), x
format long, fprintf(['format long: ']), x
format long e, fprintf(['format long e: ']), x
format long g, fprintf(['format long g: ']), x
format rat, fprintf(['format rat: ']), x % ne pas utiliser avec des nombres irrationnels
format bank, fprintf(['format bank: ']), x % format 'bancaire'

When I run it I get the following output:

How can I display the format description and the corresponding value in the same line?

I apologize if the question is a trivial one.

Thank you very much in advance.

Answer 1

[Adam Danz]

To preserve the format of the value, use formattedDisplayText, available since R2021a. This solution wraps the conversion into a function. Note that format strings no not have spaces. shortg instead of short g. If spaces are needed, you can tweek this to support the spaces.

Another benefit of this approach is that the format string is used in both the label and the conversion so there can't be a discrepancy between the label and the format.

x = 1/7;

formats = ["short" "shorte" "shortg" "long" "longe" "longg" "rat" "bank"];
for i = 1:numel(formats)
    displayFormattedValue(x,formats(i))
end

Format short: x = 0.1429
Format shorte: x = 1.4286e-01
Format shortg: x = 0.14286
Format long: x = 0.142857142857143
Format longe: x = 1.428571428571428e-01
Format longg: x = 0.142857142857143
Format rat: x = 1/7
Format bank: x = 0.14

function displayFormattedValue(val,formatStr)
    % val:  scalar value
    % formatStr: format string
    format(formatStr)
    valStr =  strtrim(formattedDisplayText(val));
    fprintf('Format %s: x = %s\n', formatStr, valStr)
end

[Steven Lord]

Note that running this code will result in the display format remaining 'bank' after it is finished executing. In order to restore the display format to its previous value I'd use the one-input and one-output form of format.

x = 1/7;

formats = ["short" "shorte" "shortg" "long" "longe" "longg" "rat" "bank"];
for i = 1:numel(formats)
    displayFormattedValue(x,formats(i))
end

Format short: x = 0.1429
Format restored to short
Value:     0.1429

Format shorte: x = 1.4286e-01
Format restored to short
Value:     0.1429

Format shortg: x = 0.14286
Format restored to short
Value:     0.1429

Format long: x = 0.142857142857143
Format restored to short
Value:     0.1429

Format longe: x = 1.428571428571428e-01
Format restored to short
Value:     0.1429

Format longg: x = 0.142857142857143
Format restored to short
Value:     0.1429

Format rat: x = 1/7
Format restored to short
Value:     0.1429

Format bank: x = 0.14
Format restored to short
Value:     0.1429

function displayFormattedValue(val,formatStr)
    % val:  scalar value
    % formatStr: format string
    % Added an output argument to this line
    fmt = format(formatStr);
    valStr =  strtrim(formattedDisplayText(val));
    fprintf('Format %s: x = %s\n', formatStr, valStr)
    % Added this line to restore the display format
    format(fmt);
    % The next two lines just shows that it works
    fprintf("Format restored to %s\n", fmt.NumericFormat)
    fprintf("Value: %s\n", formattedDisplayText(val))
end

If you want to be extra careful you could create an onCleanup object to restore the format even if the code being executed in displayFormattedValue after the initial format call throws an error before the format can be restored.

[Adam Danz]

Great thought @Steven Lord.

Here's Steven's onCleanup idea to preserve the original format.

x = 1/7;
formats = ["short" "shorte" "shortg" "long" "longe" "longg" "rat" "bank"];
originalFormat = format(); 
cleanupFormat = onCleanup(@()format(originalFormat));

for i = 1:numel(formats)
    displayFormattedValue(x,formats(i))
end

clear cleanupFormat % optional

function displayFormattedValue(val,formatStr)
    % val:  scalar value
    % formatStr: format string
    format(formatStr)
    valStr =  strtrim(formattedDisplayText(val));
    fprintf('Format %s: x = %s\n', formatStr, valStr)
end

Answer 2

[Fangjun Jiang]

use sprintf() and check "doc sprintf" to learn the % Formatting Operator

sprintf('format short: %f',x)
sprintf('format short: %e',x)

If solely for the demonstration of MATLAB Command Window formatting, use

format short, fprintf(['format short: ']);disp(x)