Identify a character in a file and edit the file from that character.

Hi,

I have a file like this:

v 347.656 -229.91 -677.344
v 218.75 -97.6563 -637.29
v 171.875 -31.25 -614.025
v 113.281 -47.0539 -618.75
v 181.448 -183.594 -661.719
v 97.6563 27.1677 -708.594
v 212.596 -50.7813 -653.906
v 155.339 -171.875 -614.844
v 62.5 -105.469 -685.376
v 292.969 -242.458 -692.969
v 105.207 15.625 -642.188
v 222.656 -238.281 -655.06
v 253.906 -93.6077 -716.406
v 210.938 19.5313 -829.752
v 43.6444 -164.063 -685.156
v 128.906 -78.125 -607.902
v 70.3125 -199.219 -650.156
v 50.7813 -257.813 -653.715
v 199.219 -212.997 -673.438
v 54.6875 -57.0634 -696.875
v 160.156 -39.0625 -619.608
# 13583 elements written

vn 0.0387398 0.926983 -0.373098
vn 0.83673 -0.0302438 0.54678
vn 0.0452287 -0.381464 0.923277
vn -0.0127617 -0.51591 0.856547
vn 0.94213 0.00369861 0.335228
vn 0.44112 -0.694334 0.568606
vn 0.63703 -0.652082 -0.411074
vn 0.498461 -0.851513 -0.162671
vn 0.822075 -0.11604 0.557429
vn -0.515863 0.473125 0.714169
vn 0.46519 -0.762386 0.449852
vn -0.478219 0.778441 0.406615
vn 0.325099 -0.500174 -0.802581
vn 0.0148388 0.0119385 0.999819
vn 0.489283 0.429513 0.759026

The numbers of lines are variable. What I need is to identify the "#" character and delete that line and all the lines under this one. Or copy all the lines above this one into a new file.

There is another character "#" in the file if it's a problem.

[Walter Roberson]

If you are on OS-X or Linux, use the system utility "sed"

sed -e '/^#/,$d' YourFileName > OutputFileName

[Jose]

nope... I'm on Windows... :(

Answer 1

[Daniel Shub]

I don't think I would use MATLAB to do this since learning sed and/or awk is really useful ... A way to do it in MATLAB

    fid = fopen('data.txt');
    data = textscan(fid, '%[^#]');
    fclose(fid);
    fid = fopen('data.txt', 'w');
    fprintf(fid, '%s\n', data{1}{:})
    fclose(fid);

[Jose]

Thank you so much!!!

It did just what I was waiting for! Well I had to do a little modification with the bufsize because of the hughe size of my files, but it worked perfectly!