if else statement

I have a for loop that used to open text files for plotting, and I want to have an if else statement that will set headerlines equal to 5 for test files having less than 500 rows, and headerlines equal to 400 for those having in excess of 500 rows. I have this so far but it does not seem to be working;

for k = 58:212
inputFileName =  sprintf('MT_%05i-000.txt',k);
      outputFileName = sprintf('results%05i.tiff',k);
      fid = fopen(inputFileName);
      newcmd=sprintf('more %s|wc -l', inputFileName); 
      [p,num_lines]=system(newcmd);
      if num_lines<=500  
      datacell = textscan(fid, '%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f','HeaderLines',5);  
      fclose(fid);
      else    
      datacell = textscan(fid, '%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f','HeaderLines',500);  
      fclose(fid);                                                                                         %number of %f reflects number of columns to record from text file  
      end

[Jan]

Please explain, what "does not seem to be working" means explicitely. It is hard to give an advice for an unknown problem, which appears in code, we cannot run. At first we do not have your data files, at second the effects of "system(newcmd)" are unknown.

[douglas]

I'm not sure exactly, someone else wrote the if else statement I have for me, and I don't know what is wrong with it, I would be open to write a new one, but I'm not sure how to go about it. When I run the file it runs every plot with headerlines set to 5 and seems to ignore the if else statement completely

[Thomas]

@Jan, here is the question that went before it: http://www.mathworks.com/matlabcentral/answers/35073-for-loop-question-plot-figure

I suggested the newcmd if the user was on linux to count the num_lines

new_cmd=sprintf('more %s|wc -l', inputFileName);

[p,num_lines]=system(newcmd);

[douglas]

oh your right you said it was for a linux based system, I'm using windows oops.

[douglas]

it seems I didn't paste that in the question, but in my script it does have the command

newcmd=sprintf('more %s|wc -l', inputFileName);

[p,num_lines]=system(newcmd);

[Thomas]

can you give me a sample of your text file.?

[douglas]

// Start Time: 0

// Sample rate: 10.0Hz

// Scenario: 1.8

// Firmware Version: 2.5.1

Year Month Day Second Temperature Acc_X Acc_Y Acc_Z Gyr_X Gyr_Y Gyr_Z Mag_X Mag_Y Mag_Z Roll Pitch Yaw AnalogIn_1 AnalogIn_2 Latitude Longitude Altitude Vel_X Vel_Y Vel_Z Status

0 0 0 0.0083 17.13 -3.602011 -0.023927 9.130322 0.002424 -0.003330 0.005214 0.551597 0.036565 -0.615183 -0.150150 21.529704 -6.936187 0 0 0.000000000 0.000000000 0.000000 0.000000 0.000000 0.000000 1

0 0 0 0.1083 17.13 -3.616401 -0.028699 9.101781 -0.013352 0.002609 -0.002676 0.546472 0.050605 -0.614217 -0.232993 21.544571 -6.953156 0 0 -0.000000001 0.000000000 -0.000094 -0.002426 -0.000193 -0.001876 1

0 0 0 0.2083 17.13 -3.626294 -0.006795 9.111114 0.005820 0.006014 0.006351 0.548270 0.048896 -0.615307 -0.185587 21.579128 -6.914592 0 0 -0.000000004 -0.000000001 -0.000314 -0.004752 0.003139 -0.002529 1

0 0 0 0.3083 17.13 -3.599662 -0.019086 9.139808 -0.003034 -0.001575 -0.005997 0.548736 0.048293 -0.615885 -0.216817 21.569953 -6.951937 0 0 -0.000000008 -0.000000004 -0.000515 -0.003222 0.004013 -0.001485 1

0 0 0 0.4083 17.13 -3.601782 -0.028687 9.101578 -0.001878 0.001172 -0.003753 0.542780 0.044977 -0.605897 -0.236359 21.576554 -6.975514 0 0 -0.000000011 -0.000000008 -0.000785 -0.003494 0.004624 -0.003916 1

0 0 0 0.5083 17.13 -3.592106 -0.028719 9.111055 -0.001411 0.002545 -0.002635 0.548381 0.045602 -0.610085 -0.250711 21.591040 -6.992247 0 0 -0.000000014 -0.000000013 -0.001272 -0.002378 0.005380 -0.005822 1

0 0 0 0.6083 17.13 -3.592194 -0.023880 9.120574 -0.012431 0.002142 -0.002905 0.545978 0.050608 -0.614250 -0.328819 21.603194 -7.010641 0 0 -0.000000015 -0.000000018 -0.001905 -0.000590 0.006776 -0.006842 1

0 0 0 0.7083 17.13 -3.631372 -0.019131 9.145054 -0.000406 0.001911 0.002302 0.547899 0.049894 -0.615344 -0.326204 21.614191 -6.996948 0 0 -0.000000016 -0.000000026 -0.002455 -0.001107 0.010194 -0.004149 1

0 0 0 0.8083 17.13 -3.601852 -0.028727 9.111190

Answer 1

[Thomas]

You could try

for k = 58:212

inputFileName =  sprintf('MT_%05i-000.txt',k);
      outputFileName = sprintf('results%05i.tiff',k);
      fid = fopen(inputFileName);

datacell=textscan(fid,'%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f');

if length(datacell)<=500   % this depends on the structure of datacell

actual_data=datacell(5:end)  % removing only the 5 headerlines
fclose(fid);

else
actual_data=datacell(401:end) % removing 400 headerlines data > 500 rows
fclose(fid);
end
end

use only the actual_data for computation

EDIT: Try the following

for k = 58:212

inputFileName =  sprintf('MT_%05i-000.txt',k);
      outputFileName = sprintf('results%05i.tiff',k);
      fid = fopen(inputFileName);

        c=textscan(fid,'%f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f','Headerlines',5,'delimiter',' ');
        if length(c{1,1})<500  % this tell us there are less than 500 elements
  datacell=textscan(fid,'%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f','Headerlines',5,'delimiter',' ');
  fclose(fid);
        else
  datacell=textscan(fid,'%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f','Headerlines',400,'delimiter',' ');
  fclose(fid);
         end
  end

[douglas]

it looks like the length(datacell) command spits out the number of columns, as I was getting it to equal 26

[Thomas]

try length(datacell{1,1})

[douglas]

it seemed to work, but now its spitting out blanks plots and says

Warning: Plot empty.

> In legend at 294

In flighttestplot65 at 105

[douglas]

since when length(c{1,1})<500

datacell = c,

I changed it to this,

inputFileName = sprintf('MT_%05i-000.txt',k);

outputFileName = sprintf('results%05i.tiff',k);

fid = fopen(inputFileName); %opens text file

c=textscan(fid,'%f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f','Headerlines',5);

if length(c{1,1})<500 % this tell us there are less than 500 elements

datacell = c;

fclose(fid);

else

datacell = textscan(fid,'%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f','Headerlines',500);

fclose(fid);

end

and it now works for those files under 500, but it doesnt like defining the new datacell in the else statement for some reason

[Thomas]

It is because the new data cells are still blank when the header lines are around 400, try the opposite:

nputFileName = sprintf('MT_%05i-000.txt',k);

outputFileName = sprintf('results%05i.tiff',k);

fid = fopen(inputFileName); %opens text file

c=textscan(fid,'%f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f','Headerlines',500);

if length(c{1,1})>1 % this tell us there are more than 500 elements

datacell = c;

fclose(fid);

else

datacell = textscan(fid,'%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f','Headerlines',5);

fclose(fid);

end

[douglas]

it now has the opposite effect, where the sub 500 row sheets appear blank, and the larger ones look great. Which is good, since 95% of my text files are large.

[Thomas]

try this

else

fid = fopen(inputFileName); %opens text file add this line again

datacell = textscan(fid,'%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f','Headerlines',5);

fclose(fid);

[douglas]

It seems to have fixed the problem!

Thank you so much for you help, you have been tremendous in assisting me!

[Thomas]

You are welcome.. Please accept the other answer as well since, it might help someone on a linux system..