I'm trying to plot a mat file with a 1x1 structure, but it's giving the error that "Index in position 2 exceeds array bounds. Index must not exceed 1."

data1 = load('radial.mat');  % Assume data is [X1 Y1] for file1
plot(data1(:,1), data1(:,2), 'g', 'DisplayName', 'File 2');

[Stephen23]

"Assume data is [X1 Y1] for file1"

I would assume that it is a scalar structure, just like the LOAD documentation explains:

https://www.mathworks.com/help/matlab/ref/load.html#description

Answer 1

[Star Strider]

When you load into a variable, that creates a structure. The information you want will then be in that structure.

data1 = load('radial.mat'); % Assume data is [X1 Y1] for file1

So for example if ‘data1’ defines the variable ‘radial’ (I actually have no idea what is in it, since I do not have access to it), the information you want will be in

data1.radial

The easiest way to get it would be to define:

radial = data1.radial;

That should work, and then you can execute:

figure

plot(radial(:,1), radial(:,2))

grid

Loading data into a structure is actually good practice, because you can then choose the variables you want to work with (if there are more than one in the .mat file) without filling your workspace with all of them.

.

EDIT — Corrected typographical errors.

.

[Heather]

this is what is in the file, it's still giving the same error about exceeding array bounds

data: [-0.0128 -0.0130 -0.0129 -0.0127 -0.0122 -0.0116 … ]

• the data is a 1x22620 double

datastart: 1

dataend: 22620

titles: 'Channel 1'

rangemin: -2

rangemax: 2

unittext: 'V'

unittextmap: 1

blocktimes: 7.3965e+05

tickrate: 1000

samplerate: 1000

firstsampleoffset: 0

comtext: ''

com: [0×5 double]

[Stephen23]

" it's still giving the same error about exceeding array bounds"

Please show us the exact code that you are using.

It would also help if you uploaded the MAT file by clicking the paperclip button.

[Star Strider]

The data vector needs an associated time vector, and ideally should have a time vector or a sampling frequency associated with it, as an additional variable that you can retrieve just as you did the ‘data’ vector.. You can easily create the necessary time vector from the sampling frequency.

Please provide the radial.mat file.

[Heather]

https://mail-attachment.googleusercontent.com/attachment/u/0/?ui=2&ik=57a2ce187f&attid=0.1&permmsgid=msg-f:1822612679740179847&th=194b38935b094587&view=att&disp=safe&realattid=f_m6iatvu52&zw&saddbat=ANGjdJ_bhQXGa93rPOHlbSAnl4tYgdrCgEZsZseWJu6k7abKfmAm2vhjlwo1PBzFOhmUxaLDHH2X4BcS9vMZBVWZaQf5BNOi8j7Z_2JpVwxGN3P9dGskxV2KYxQjdnBqdSS9JYQcHxVSBy8HZXyRZLffavvE-a2FSOd9IH_4tMBSQDKzY3G9a7t-5mJtgVl_tBfSi9naRT1PLym5Mp-x50tGC38fZ6Q1tk5pdTZH6IT8_9OVVamgT3gPR2elegj4uR8CrH5HSW8Tr-DuUIKTVPiVJpwirb_uWrlzvVV9XJpfaeMp4kLPWXeJwp_24VrlvF_nk534JGK-MxseFxPkBVsHRF8oXrUQnSuDZ4RamoNRlQpaXITtiPhMjGfwKaUhW4-ZRz5sw4VtBXOEZh-P_6pHVs941f0D4jGiK4Ek-Qhko_SBlThnqXh6nM4b2NLwC7dznFQcCVhX8icBvXq6sR1dySYLSoAzdq7hNSNwiMgmcKIjrTp9Md6GiaS0csKtoXjsusow57Xb3BFaf7q167hISIAaPOgtYyZ7RDlsHWjClOZVNmTiSCdPcw7KWvQtm_Jln4AGBjbpbxfWcIT-X6-mkYaruJK4AXwd70f-3khFkGeKdGNWmSwOnRhO5u4MYFSh4VK7brqT7X2jMcxQyLOPHhEV38Q1NMMZjwvQNpA4iOFysCArYtAIp8ftA67X3Kfua4muGVXWPKs7T7L1wQxVCJ1mmLrNzydSDOFl6FP-VQaX2QsjuGZoUduDDShWYT13cuCJ4xXXkpjab6ID-1gmMMQcjEgm6PfJicZhM7k5vUvHGSi_Ari2zQFoTRKI6eREsz7Yl-ZCHmJlNu1Xh312UeF27A729NGTnUSp7Ds4sjA9N3Ie1d6KaAM4wkjb4D5TiXJPcLh98fq0ji2lImVENp95Kh5iYKdWOYr-iC8PB0CxbJkYS4ppg2kJJWayRVLkrZC8UUdYlbjiM7dm6pbZpy8tPfOw2RV_l50dOjJumC8x7nYyL2rteHahle8UauwrQj5LuctU1bAbUX4K28ZQ5tee0L6NpphiBL5HS4mTXmelETTiPnHksBanuk_QQjK9TdkdJym6G0he7ja4gcQdV5EbSNyRVKguemg8Fw

[Heather]

this is the mat file

[Star Strider]

There’s no file there. It’s just the gmail homepage.

I can’t access the file.

Can you upload it here (using the paperclip icon in the totp toolstrip)?

[Heather]

does it work ?

[Walter Roberson]

load('radial (2).mat');
data1 = data;
plot(data1(:,1), data1(:,2), '*-g', 'DisplayName', 'File 2');

  Name                   Size                Bytes  Class     Attributes

  ans                    1x38                   76  char                
  blocktimes             1x1                     8  double              
  com                    0x5                     0  double              
  comtext                0x0                     0  char                
  data                   1x22620            180960  double              
  data1                  1x22620            180960  double              
  dataend                1x1                     8  double              
  datastart              1x1                     8  double              
  firstsampleoffset      1x1                     8  double              
  rangemax               1x1                     8  double              
  rangemin               1x1                     8  double              
  samplerate             1x1                     8  double              
  tickrate               1x1                     8  double              
  titles                 1x9                    18  char                
  unittext               1x1                     2  char                
  unittextmap            1x1                     8  double              

Note that data1 is a 1x22620 double, so data1(:,1) is a scalar and data1(:,2) is a scalar. By default plot() only draws lines if there are at least two adjacent finite points; when you plot only a scalar there is only one point. That is why I added the marker code '*' so that the scalar point would show up.

whos

You do not have any variable of comparible size to data(), so there is no typing mistake there.

It is possible that you want

data1 = reshape(data, 2, []);

or

data1 = reshape(data, [], 2).';

[Heather]

is there a way to get it into a graph form instead of just a point, or is that how they file shows up?

[Stephen23]

Using the recommended approach of LOADing into an output variable:

S = load('radial (2).mat')  % the output is a scalar structure

S = struct with fields:
                 data: [-0.0128 -0.0130 -0.0129 -0.0127 -0.0122 -0.0116 -0.0111 -0.0106 -0.0098 -0.0093 -0.0091 -0.0093 -0.0093 -0.0094 -0.0097 -0.0102 ... ] (1x22620 double)
            datastart: 1
              dataend: 22620
               titles: 'Channel 1'
             rangemin: -2
             rangemax: 2
             unittext: 'V'
          unittextmap: 1
           blocktimes: 7.3965e+05
             tickrate: 1000
           samplerate: 1000
    firstsampleoffset: 0
              comtext: ''
                  com: [0x5 double]

"is there a way to get it into a graph form instead of just a point, or is that how they file shows up?"

Taking a wild guess (because your code and explanations do not match the data from that file):

plot(S.data, 'g', 'DisplayName', 'File 2');

[Star Strider]

The ‘data’ variable looks like a Lead I EKG.

I am not sure what you want to do with it, so I let my imagination run wild —

LD = load('radial (2).mat')

LD = struct with fields:
                 data: [-0.0128 -0.0130 -0.0129 -0.0127 -0.0122 -0.0116 -0.0111 -0.0106 -0.0098 -0.0093 -0.0091 -0.0093 -0.0093 -0.0094 -0.0097 -0.0102 ... ] (1x22620 double)
            datastart: 1
              dataend: 22620
               titles: 'Channel 1'
             rangemin: -2
             rangemax: 2
             unittext: 'V'
          unittextmap: 1
           blocktimes: 7.3965e+05
             tickrate: 1000
           samplerate: 1000
    firstsampleoffset: 0
              comtext: ''
                  com: [0x5 double]

data = LD.data;
Fs = LD.samplerate;                                             % Sampling Frequency
t = linspace(0, numel(data)-1, numel(data))/Fs;                 % Create Time Vector

[pks,locs] = findpeaks(data, MinPeakProminence=0.075);          % Deteect R-Waves

Rtimes = t(locs);

Rrates = 60./diff(Rtimes);
Rrate_mean = mean(Rrates)

Rrate_mean = 67.7028

Rrate_std = std(Rrates);
R_sem = Rrate_std/numel(Rtimes);
Rrate_CI95 = tinv([0.025 0.975], numel(Rrates)-1) * R_sem + Rrate_mean

Rrate_CI95 = 1×2

67.1369 68.2687

<mw-icon class=""></mw-icon>

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figure
plot(t, data)
hold on
plot(Rtimes, pks, 'vr')
hold off
grid
xlabel('Time (s)')
ylabel('Amplitude')
title('data')

●

figure
plot(t, data)
grid
xlim([4.5 7.5])
xlabel('Time (s)')
ylabel('Amplitude')
title('data (Detail)')
xline([5.92 6.18], '--k')
text(5.94, 0.175, '\rightarrow', Horiz='right')
text(6.18, 0.175, sprintf('\\leftarrow %.0f ms', (6.18-5.94)*1E+3))

figure
histogram(Rrates, 10, Normalization='probability')
grid
xlabel('R Rate')
ylabel('Frequency')
title('Rate Histogram')

figure
histfit(Rrates, 10, 'lognormal')
grid
xlabel('R Rate')
ylabel('Frequency')
title('Probability Histogram With Lognormal Distribution Fit')

Beyond that, the QRS complexes appear to be significantly wider than they should be (120 ms maximum). The P-waves appear to be absent, however the rate is too high for this to be an escape rhythm, so they likely do not project well onto this lead. Mild baseline variation. There is significant R-wave amplitude variation, perhaps a movement artefact.

Impression: Significant intraventricular conduction delay.

.

[William Rose]

Plus 1 for @Star Strider's analysis. Very impressive.

[Star Strider]

@William Rose — Thank you!