# How to add percent change in barplot?

조회 수: 17 (최근 30일)
Daphne PARLIARI 2021년 1월 4일
댓글: Daphne PARLIARI 2021년 1월 4일
Hello everyone and happy new year!
I have a barplot (average deaths per degree of temperature, 30-37oC) to which I want to add the percentage change from bar to bar. Attached you can find the excel file I am proccessing and here is the part of code that produces tha barplot.
Is there an efficient way to do so?
PS. I am on R2019a.
idx = Daily_Data.Daily_T(:) > 30;
Daily_Data_new = Daily_Data(idx,:);
[G, Temperature] = discretize(Daily_Data_new.Daily_T, 30:37);
d_mean = accumarray(G, Daily_Data_new.Daily_Deaths, [length(Temperature), 1], @mean);
bar(Temperature, d_mean); xlabel('T (oC)'); ylabel('Average deaths');

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### 채택된 답변

Steve Eddins 2021년 1월 4일
편집: Steve Eddins 2021년 1월 4일
If you want text labels instead of a line plot (Cris' suggestion), then try this code. It gets the Bar object as the output argument from bar, and then computes the percent change and where to put the labels using the XData and YData properties of the Bar object.
b = bar(Temperature, d_mean); xlabel('T (oC)'); ylabel('Average deaths');
x = b.XData;
y = b.YData;
percent_change = 100 * diff(y) ./ y(1:end-1);
for k = 1:length(percent_change)
text(x(k+1),y(k+1),sprintf('%0.1f%%',percent_change(k)),...
'HorizontalAlignment','center',...
'VerticalAlignment','bottom')
end
##### 댓글 수: 3이전 댓글 1개 표시이전 댓글 1개 숨기기
Steve Eddins 2021년 1월 4일
reference_temp = y(1); % 30oC in plot
percent_change = 100 * (y - reference_temp) / reference_temp;
Daphne PARLIARI 2021년 1월 4일
With this code below
x = b.XData;
y = b.YData;
reference_temp = y(1); % 30oC in plot
percent_change = 100 * (y - reference_temp) / reference_temp;
for k = 1:length(percent_change)
text(x(k+1),y(k+1),sprintf('%0.1f%%',percent_change(k)),...
'HorizontalAlignment','center',...
'VerticalAlignment','bottom')
end
I am getting the Error: Index exceeds the number of array elements (8).

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### 추가 답변 (1개)

Cris LaPierre 2021년 1월 4일
You can add a line plot to a bar plot. Just use the hold on command.
If you need it to be on a separate Y scale, look at this example
##### 댓글 수: 1이전 댓글 -1개 표시이전 댓글 -1개 숨기기
Daphne PARLIARI 2021년 1월 4일
Thank you Cris! Since I am not very experienced in MatLab, Steve's answer was easier for me to comprehend...

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