Data extraction and indexing of array

Hi,

I have a structure of 1x5 and I want to extract X and Y position data of each individual in a single variables like posxdata, posydata, velxdata, velydata, against nid. The nid can range from 1 to 5000 depending upon the time duration.

Since here all the nid [1 to 5] has x and y values of 1x51. Kindly let me know if they have different values like

nid(1) =length(x) = 51 nid(1) =length(y) = 51

nid(2) =length(x) = 43 nid(2) =length(y) = 43

nid(3) =length(x) = 29 nid(3) =length(y) = 29

nid(4) =length(x) = 91 nid(4) =length(y) = 91

nid(5) =length(x) = 81 nid(5) =length(y) = 81

I have written this simple program to extract data. But I am facing dimension mismatch issue.

    nid = 5;
    xposdata = np.x;
    yposdata = np.y;
    for i= 1:nid
        for j = 1: length(xposdata|yposdata)
        xposdata(i,j) =np(i).x(1:end)
        yposdata(i,j) =np(i).y(1:end)
        velxposdata(i,j) =np(i).vx(1:end)
        velyposdata(i,j) =np(i).vy(1:end)
        end
    end

nid = 5;
xposdata = np.x;
yposdata = np.y;
velxposdata= np.v_x;
velyposdata= np.v_y;
for i= 1:nid
    for j = 1: length(xposdata|yposdata)
    xposdata(i,j:end) =np(i).x(1:end);
    yposdata(i,j:end) =np(i).y(1:end);
    velxposdata(i,j:end) =np(i).v_x(1:end);
    velyposdata(i,j:end) =np(i).v_y(1:end);
    end
end

I need your guideline and recommendation of some short course which can develop understanding of data extraction and manipulation. Mat file is attached thanks

Thanks

[Arsal15]

Secondly, I should use scatter or plot to plot all those data sets ?

Answer 1

[Sudheer Bhimireddy]

If your data size changes throughout the structure then load them into a cell array and access each entry.

nid = 5;
xposdata = np.x;
yposdata = np.y;
velxposdata= np.v_x;
velyposdata= np.v_y;
for i= 1:nid
    xposdata{i}    = np(i).x(1:end);
    yposdata{i}    = np(i).y(1:end);
    velxposdata{i} = np(i).v_x(1:end);
    velyposdata{i} = np(i).v_y(1:end);
end

% for plotting them
h=figure;
clf;
hold on;
for i =1:nid
    x = xposdata{i};
    y = yposdata{i};
    plot(x,y);
end

[Arsal15]

Hi Sudheer Bhimireddy,

I tried this solution and error is same. I have attached new NP.mat with x,y data has different length.

[Sudheer Bhimireddy]

My bad. Before the for loop the xposdata and similar variables are already initialized.

Change them to:

xposdata    = cell(nid,1);
yposdata    = cell(nid,1);
velxposdata = cell(nid,1);
velyposdata = cell(nid,1);