Unable to Plot in For Loop

Question

Cameron Power 2018-7-20

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/411333-unable-to-plot-in-for-loop

回答： Steven Lord 2018-8-3

I am trying to make a two y-axis plot in a for loop using the code below:

t = 10;
for n = 1:t
  TempFile = sprintf('%s%d', 'ShearEnv_top', n);
  m = hour(TempFile(:,5));
  plot(m, TempFile(:,12) .* 10, 'b-'), ylim([0 360]), grid minor, ylabel('Wind Direction (degrees)'), xlabel('Time of Day(Hr)'), title('Daily Wind Direction Patterns');
    yyaxis right, plot(m, TempFile(:,14) ./ 3.6, 'g-')
  end

However when I run it I get the error;

"Error using plot
Invalid first data argument.
Error in Keep_3 (line 8)
    plot(TempFile(:,5), TempFile(:,12) .* 10, 'b-'), ylim([0 360]), grid minor, ylabel('Wind Direction (degrees)'), xlabel('Time of Day(Hr)'), title('Daily Wind Direction Patterns');'

I`ve tried using the hour function but I either get an error when using brace brackets for;

Or an error that the input is of type 'char'

t = 10;
for n = 1:t
  TempFile = sprintf('%s%d', 'ShearEnv_top', n);
  m = hour(TempFile(:,5));
  plot(m, TempFile(:,12) .* 10, 'b-')
  ylim([0 360]), grid minor
  ylabel('Wind Direction (degrees)'), xlabel('Time of Day(Hr)'), title('Daily Wind Direction Patterns');
  yyaxis right, plot(m, TempFile(:,14) ./ 3.6, 'g-')
end
"Undefined function 'hour' for input arguments of type 'char'.
Error in Keep_3 (line 8)
    m = hour(TempFile(:,5));"

I have made plots in Matlab R2017a with this code but in Matlab R2018a these errors arise.

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Viren Gupta 2018-8-3

在 MATLAB Online 中打开

I tried this in R2018a.

       TempFile(:,5) % value = 'r'.
      What does parsing 'r' in hour function mean?

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Answer 1

Steven Lord 2018-8-3

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/411333-unable-to-plot-in-for-loop#answer_331496

It looks like TempFile is the name of a file that you want to read into MATLAB, but you skipped the actual file reading step.

Alternately, it could be the name of a variable (one in a series of sequentially named variables) that you want to use, but if that's the case you shouldn't do that. Use the alternative approaches described on that page instead.