Create a text file using Matlab - matlab

Question

I'm trying to make some changes in a list of precipitation data.
The data are in a *.txt file in this format:
50810,200301010600,0.0
50810,200301010601,0.0
50810,200301010800,0.0
50810,200301010938,0.1
50810,200301010947,0.1
50810,200301010957,0.1
Each file I have contains precipitation data per minute from 1 year.
The first number is just the station number, and this is equal for each line in the file.
In my original file, I have one line with data for every minute.
I want to make a new file that contains:
Only lines with precipitation that is not zero, so I want to remove
all the lines where the last number is zero. I've figured this out.
If there is one whole hour with no precipitation, I want to remove all
of the zero-lines and create a new line which says:
50810,200301010600,0.0. If there was no precipitation between 6 and 7
am. at the 01.01.
clear all
data = load('jan-31des_2003.txt'); %opens file with data
fid=fopen('50810_2003','w'); %opens empty file to write
[nrow, ncol] = size(data); %size of data
fprintf(fid,'%5s %12s %5s \r\n','Snr','Dato - Tid','RR_01') %Header
for row = 1:nrow
y = data(row,2); %year
m = data(row,3); % month
d = data(row,4); % date
h = data(row,5); % hour
M = data(row,6); % minute
p = data(row,8); % precipitation
if p > 0
fprintf(fid,'50810,%04d%02d%02d%02d%02d,%.1f \r\n',[y,m,d,h,M,p]);
end
if p==0
HERE I NEED SOME HELP
end
end
fclose(fid);
What is the code for my desired formatting within the if p==0 condition?

Answer 1

Assuming you've already imported your data as an M*3 array named infile and M is divisible by 60 and your data begins at the first minute of an hour, and you have an array outfile that will be written to a new file:
outfile = []
while ~isempty(infile)
block = infile(1:60,:); % Take one hour's worth of data
if sum (block(:,3)==0) == 60 % Check if the last column are all zero
outfile = cat(1, outfile, [block(1,1:2), 0]); % If so, put one line to new array
else
filter = block(:,3)~=0; % Otherwise, pick out only rows that the last column is not zeros
outfile = cat(1, outfile, block(filter,:)); % Put these rows into the new array
end
infile(1:60,:) = []; % Remove already processed data from original array
end
Then write the entire outfile array to file.