Counting the from when data changes to 0 then changes back to a number

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Franchesca 2014-5-13

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关闭： MATLAB Answer Bot 2021-8-20

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This is my code:

%% Import data

numfiles = 54; % number of excel files mydata=cell(numfiles,1); % defining size of mydata d=dir('Trial*.csv');

for i=7:length(mydata) % loop to import mutliple excel files

try

mydata{i} = xlsread(d(i).name); % import files into mydata

catch

disp([d(i).name 'read failed'])

end

myfilename = sprintf('Trial%02d.csv', i); % define file name
mydata{i} = xlsread(myfilename); % import files into mydata

%% Perfrom Calculations

    %%Define variables 
      a= 9.81; % acceleration
      fps = 250; % frames per second
    %%Calculate Jump Height  
      no_of_zeros(i,1) = size(mydata{i,1},1) - nnz(mydata{i,1}(:,5)); %number of zeros
      no_of_frames = (no_of_zeros(i,1)/4); % number of frames 
      time = ((no_of_frames/fps)/2); % time up
      jumph(i,1)=((a*(time*time))/2); % jump height

Looking at the calculate jump height, it calculates correctly for the first 2 trials but then gives large over estimations for nealry all the other trails. It was a while ago I wrote this could someone clarify this line of code for me as this is where the trouble lies, I'm unsure with the ,1.

no_of_zeros(i,1) = size(mydata{i,1},1) - nnz(mydata{i,1}(:,5)); %number of zeros

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Azzi Abdelmalek 2014-5-13

Franchesca, zeros are also numbers. Your question and your comment are different. Do you need to count the number of zeros or how many time they switch from zero to non zero?

Franchesca 2014-5-13

Sorry, from the numbers to zeros so count the number of zeros from the point in the column where the first zero appears to where that block of zeros ends.

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Answer 1

Azzi Abdelmalek 2014-5-13

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/129497-counting-the-from-when-data-changes-to-0-then-changes-back-to-a-number#answer_136697

编辑：Azzi Abdelmalek 2014-5-13

在 MATLAB Online 中打开

 a=[1 1 0 0 4 5 0  0 7 4 7 0 0 0 7]
idx=[ 1 a~=0 1]
ii=strfind(idx,[1 0])
jj=strfind(idx,[0 1])
out=jj-ii

Counting the from when data changes to 0 then changes back to a number

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Counting the from when data changes to 0 then changes back to a number

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