Data labels above bars on grouped bar plot

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Justin Solomon
Justin Solomon on 16 May 2014
Answered: Halina H on 7 Dec 2017
I'm making a grouped bar plot (i.e., a bar plot with multiple bars in each category). I would like to add labels at the top of each bar to indicate its height. I was planning to just use the text function. However, bars within a given group all have the same x location (i.e get(h,'XData') is the same for all bar series). I'm not sure how to find the proper x location for each bar within a given group. Any ideas?
Thanks, Justin
  2 Comments
dpb
dpb on 30 Jun 2016
Submit the enhancement request to TMW @ www.mathworks.com

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Accepted Answer

dpb
dpb on 16 May 2014
Edited: dpb on 16 May 2014
You're on the right track, the center of each group is at the axis tick value. For each bar in the group, use that value plus/minus a delta to locate the x position for your text.
I did an example of this for another poster within the last few weeks at most altho I don't have the link at hand. Perhaps a search will uncover it.
ADDENDUM:
OK, I looked at past answers--this one is pretty close altho I thought I did another. Maybe it was in the newsgroup instead...
  6 Comments
dpb
dpb on 3 Oct 2016
Just past 'em together...
Y=[Y1;Y2;Y3].'; % create nx3 column array for *bar*
NB: The latest release of bar uses HG2 and returns a handle to a barobject, rather than the former bar series objects. This new object is essentially opaque to the the details and the data for the patches used to draw the bars isn't available from which to compute the individual bar positions so labelling bars as this example does won't work. I've not got a more recent version so not sure what the workaround is, if there is one or if one must resort back to the earlier "trick" I illustrated before.

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More Answers (5)

Will Adler
Will Adler on 18 Nov 2014
This doesn't work in R2014b any more, due to this.
The available bar series properties no longer have the info for the location of the bar. Any idea how to recreate this in grouped bar plots?
  8 Comments
Kelly Kearney
Kelly Kearney on 21 Sep 2016
Moving the labels inside the bars is a simple matter of changing the horizontal alignment so the right edge, rather than left, aligns with the bar height (and in most cases, adding a small offset to the y-position so the text doesn't sit flush to the bar edge).
This example also assumes that your bars are all large enough to fit the full text string.
Y=random('unif',30,100,[4 3]); % sample data
h=bar(Y);
yb = cat(1, h.YData);
xb = bsxfun(@plus, h(1).XData, [h.XOffset]');
hold on;
padval = 1;
htxt = text(xb(:),yb(:)-padval, cellstr(num2str(yb(:))), ...
'rotation', 90, 'horiz', 'right');
set(htxt(1:3:end), 'color', 'w'); % for legibility

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Image Analyst
Image Analyst on 17 May 2014
For what it's worth, see attached demo. Adapt as needed.
  1 Comment
Justin Solomon
Justin Solomon on 17 May 2014
Thanks for your comments. The difference in the case you show here and my case is that your bars are all centered on the ticks. If you have bar groups, then you have multiple bars grouped about the same xtick (see the image link in my original post). The only way I was able to figure out the exact center location of the each bar within a group was to get info from the underlying patch objects that are created when bar() is called. See my code above for an example.

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aliyar attaran
aliyar attaran on 4 Nov 2016
for 2 bars one one y value:
for i2=1:numel(y)
tx(i2,1)=text(x(i2),y(i2,1),num2str(y(i2,1),'%0.2f'),...
'HorizontalAlignment','right',...
'VerticalAlignment','bottom');
tx(i2,2)=text(x(i2),y(i2,2),num2str(y(i2,2),'%0.2f'),...
'HorizontalAlignment','left',...
'VerticalAlignment','bottom');
end

Elimelech Schreiber
Elimelech Schreiber on 5 Nov 2017
I've written a function to do just this. It's called barvalues, and is very easy yo use.
simply:
bar(x);
barvalues;
  2 Comments
dpb
dpb on 6 Nov 2017
I munged on your function some...haven't tested it thoroughly but it now works for the above case...haven't tried for more exotic examples. I know it won't work correctly for 'stacked' as the YData property isn't correct y location for it--not sure if it is retrievable or must be recomputed.
Modifications include
  1. fixing up isaType to look at all objects in handle array rather than just one (this may be too simplistic in some cases, I don't know; didn't study the search logic enough to know if could possibly pass a group that might be other than bar handles)
  2. using only one of the array handles in axes call to get axes handle (this could also possibly(?) be too simplistic if there are multiple bar objects but in multiple axes on a given figure), and
  3. looping over the handle array and adding the .XOffSet property differential to the text call.
Doesn't seem an easy way to add updates at the Exchange so I'll just paste the modified routine here for your convenience...

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Halina H
Halina H on 7 Dec 2017
Hi , I would like to know how to code to get the total value of each bar in this grouped bar graph ie , total bincounts for the yellow bar, total bincounts for blue bar , and total bincounts for green bar. I am interested to know which of these 3 bars give the most information

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