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Display number with engineering notation

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Jared
Jared on 8 Nov 2011
Edited: Harry Dymond on 31 May 2020
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.

  1 Comment

Harry Dymond
Harry Dymond on 31 May 2020
For the benifit of those stumbling across this old thread in search of answers: please see my answer below

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Accepted Answer

Walter Roberson
Walter Roberson on 8 Nov 2011
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

  2 Comments

Jared
Jared on 9 Nov 2011
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
Walter Roberson on 9 Nov 2011
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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More Answers (2)

owr
owr on 8 Nov 2011
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.

  1 Comment

Jared
Jared on 8 Nov 2011
As far as I know, sprintf does not have a engineering notation format string.

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Harry Dymond
Harry Dymond on 31 May 2020
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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