Displaying exponential notation with num2str?
显示 更早的评论
I have a value that I want to display within a textbox in a figure. The value hoewer needs to be in exponential notation.
Example:
lambda = 2.4321;
vD = 3.2e5;
fighandle = figure(1);
fighandle.Color = [1,1,1];
fighandle.Position = [10,50,600,400];
fighandle.Name = 'Test';
xlabel('t [min]','FontSize',12,'Interpreter','latex');
ylabel('Temperatur [$^\circ$C]','FontSize',12,'Interpreter','latex');
annotation('textbox', [0.66, 0.15, 0.1, 0.1], ...
'String', {['$\lambda$ = ' num2str(round(lambda,3),'%.3f') ' W/mK'], ...
['$v_D$ = ' num2str(round(vD,1),'%.1f') ' m/s']}, ...
'BackgroundColor', 'White', ...
'Interpreter','latex');
The result looks like this:
But i want the variable b to look like this:
Any ideas? Thank you very much for the help!
采纳的回答
I wrote a little utility program to do that sort of thing a few years ago.
Try this —
Q1 = [-pi*1000; 0; pi*100];
expstr = @(x) [x(:).*10.^ceil(-log10(abs(x(:)+(x==0)))) floor(log10(abs(x(:)+(x==0))))]; % Updated: 2021 05 04
Result = sprintf('%+.4fe%+04d\n', expstr(Q1).')
V = expstr(Q1)
Create the sprintf format string (that I use here) to give the result you want.
.
2 个评论
Thank you very much! That did, what I was looking for :)
I implemented it this way within the annotation textbox:
vD_expstr = expstr(vD);
% ...
['$v_D$ = ' num2str(round(vD_expstr(1),1),'%.1f') ' $\cdot$ 10' num2str(vD_expstr(2),'$^{%.0f}$') ' m/s']
Star Strider
2022-8-24
As always, my pleasure!
That will work, since num2str allows format strings, although sprintf might be an easier way to implement it.
I created ‘expstr’ precisely for the purpose you’re using it!
更多回答（1 个）
Another function that might be of interest to you is formattedDisplayText, if you want to capture how the variable would be displayed in MATLAB using a certain display format.
x = pi
y1 = formattedDisplayText(x)
format longeng
x
y2 = formattedDisplayText(x)
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