Display number with engineering notation

Question

Jared 2011-11-8

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编辑： Harry Dymond 2020-5-31

I'm trying to display a number I read in with textscan in engineering notation. I was trying to switch the format to short eng and do:

evalc('disp(x)')

But it doesn't matter what format I set, the format textscan reads it in is what it uses.

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Harry Dymond 2020-5-31

编辑：Harry Dymond 2020-5-31

For the benifit of those stumbling across this old thread in search of answers: please see my answer below

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Answer 1

Walter Roberson 2011-11-8

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在 MATLAB Online 中打开

My tests disagree with Jared's findings:

>> result = textscan('133423.3e7','%f')
result = 
    [1334233000000]
>> format short eng
>> evalc('disp(result{1})')
ans =
     1.3342e+012
>> result{1}
ans =
     1.3342e+012

Engineering format was indeed used for the output, and the output is not the same as the format of the value that was read in nor of the format the data was stored in

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Jared 2011-11-9

During more experimentation, it works for an example like the one you posted. However, and I guess I forgot to put it in my original question, I am actually trying to set the string in a GUI using

set(handles.example,'String','example string'). For some reason, it does not seem to follow these formatting inputs.

Walter Roberson 2011-11-9

Trying to set as input or as output? Are you using

textscan( get(handles.example,'String'), 'Some Format Here')

or are you using

set(handles.example, 'String', x) %where x is the numeric value

or are you using something like:

set(handles.example, 'String', evalc('format short eng; disp(x)'))

If you are trying to set the String parameter to a numeric value, then the conversion that MATLAB uses is not documented (as best I recall.)

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Answer 2

Harry Dymond 2020-5-31

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For the benifit of those stumbling across this old thread in search of answers: my FEX submission num2eng will do this, and offers SI prefixes as well as engineering notation.

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Answer 3

owr 2011-11-8

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Try sprintf with a format string. It converts the number to a text string with a format of your choosing. Some built in MATLAB functions use this trick, for example, edit the code for dlmread.