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How to add annotations to a plot by accessing data from a table?

Asked by Kathyayani Nandakumar on 6 Sep 2019
Latest activity Commented on by Cris LaPierre
on 8 Sep 2019
I have a table with a combination of strings and numbers as follows:
A 0 1
B 5 0
C 0 1
D 0 0
E 3 4
This table is used to add annotations to a plot. The idea is to display rows with non zero values in it, i.e., in plot 1, I need to display B-5, E-3 and in plot 2, A-1, C-1, E-4, as shown in the image below.
Can someone suggest a way for doing this in matlab? Thanks in advance!!

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1 Answer

Answer by Cris LaPierre
on 8 Sep 2019

Use the text function.
You can use sprintf to build the text to display on the plot.
If you need it to be automated, use logical indexing to identify which rows contain non-zero entries. Here's a quick attempt:
% create the initial plots
theta = 0:0.1:2*pi;
siny = sin(theta);
cosy = cos(theta);
subplot(1,2,1)
plot(theta, siny)
subplot(1,2,2)
plot(theta,cosy)
% Now add text
for p = 2:width(dispTxt)
idx = dispTxt{:,p} > 0;
txt = sprintf("%s-%s\n",[dispTxt{idx,1},dispTxt{idx,p}]');
% Select desired subplot
subplot(1,2,p-1)
xlim([0 8])
text(7,-0.5,txt)
end
Of course, you could also add the text at the same time you are creating the plots.

  1 Comment

BTW, dispTxt is a table containing the values you showed in your question.
T = ["A" "B" "C" "D" "E"];
V1 = [0 5 0 0 3];
V2 = [1 0 1 0 4];
dispTxt = table(T',V1',V2')

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