Plot bar chart from elements of string

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Madlab 2018-9-26

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编辑： Stephen23 2018-9-26

file.mat

I want to create a bar graph showing the number eruptions for the respective countries. However, the data provided is in a string and I need to loop through the data set to count the respective countries. As it is in a string format, I am struggling to extract out the number of counts for each country in a loop. I managed to use strcmp and find, but the plot does not work. How do I create a loop which plots the chart sucessfully?

% Finding each individual country "eachcountry"
eachcountry = unique(thecountry);
% Counting the length of year for j
% loop through each index 
for j = 1:length(thecountry)
      A = strcmp('%s'eachcountry(j),thecountry);
      % Obtaining index of respective country
      indexcountry = find(A)
      numberofcounts =  numel(indexcountry);
      % Plotting with rectangle function, start from the first year, for x axis, 
      % start from 0 for y axis. Width is 1, while frequency is number of
      % counts.
      rectangle('Position',[eachcountry(j) 0 1 numberofcounts])
      hold on
  end
% Labelling axes
xlabel('Country')
ylabel('Frequency')

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Answer 1

Stephen23 2018-9-26

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编辑：Stephen23 2018-9-26

在 MATLAB Online 中打开

>> [U,~,X] = unique(thecountry);
>> cnt = histc(X,1:numel(U));
>> bar(cnt)

creates this:

You might want to read this too:

https://www.mathworks.com/matlabcentral/answers/128396-how-do-i-label-the-bars-in-my-bar-graph-in-matlab

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Madlab 2018-9-26

Thank you very much for your input. What I am trying to plot is more like this image here, showing the counts for each respective country. That is why I am trying to utilise the loop to count each country and plot it.

Stephen23 2018-9-26

编辑：Stephen23 2018-9-26

在 MATLAB Online 中打开

@Madlab: see my edited answer, which plots the number of eruptions for each country. No loops are required. You can easily add country labels too:

>> set(gca,'XTick',[])
>> cellfun(@(x,s)text(x,-1,s,'Rotation',270),num2cell(1:numel(U)),U.')

Giving:

With newer MATLAB versions you can simply add the names as XTickLabel and set the XTickLabelRotation directly, no need for text.

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Answer 2

jonas 2018-9-26

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编辑：jonas 2018-9-26

在 MATLAB Online 中打开

something like this?

n=ones(size(thecountry))
[G,ctr]=findgroups(thecountry)
nrupt=splitapply(@sum,n,G)
bar(nrupt)
set(gca,'xtick',1:size(nrupt,1),'xticklabel',ctr,'xticklabelrotation',90,'fontsize',7,'ticklength',[0 0])