Removing double empty lines from a text file
显示 更早的评论
If a file contains more than one consecutive empty lines, they are replaced by one empty line.
% reading file
fid=fopen(outFile,'rt');
Data = textscan(fid,'%s','Delimiter','\n');
Data=Data{1}; % get rid of nesting
k=1; emptylines_occured=0;
for j=1:numel(Data)
if ~strcmp(Data(j),'') % not empty line
if emptylines_occured
newData{k}=''; k=k+1;
emptylines_occured=0;
end
newData(k)=Data(j); k=k+1;
else % empty line
emptylines_occured=1;
end
end
fclose(fid);
% writing file
fid=fopen(outFile,'wt');
for j=1:numel(newData)
fprintf(fid, '%s\n',newData{j});
end
fclose(fid);
Is there a more concise way?
采纳的回答
You can easily write the new file at the same time as you read the old one, which is faster and uses much less memory. Here is a simple version that create the new file with at most one empty line between any two non-empty lines:
[f1d,msg] = fopen('test_old.txt','rt');
assert(f1d>=3,msg)
[f2d,msg] = fopen('test_new.txt','wt');
assert(f2d>=3,msg)
prv = 'X';
while ~feof(f1d)
new = fgetl(f1d);
if numel(new) || numel(prv)
fprintf(f2d,'%s\n',new);
end
prv = new;
end
fclose(f1d);
fclose(f2d);
The test files are attached. Define prv as an empty char to ignore the leading empty line/s.
3 个评论
Walter Roberson
2018-2-8
Be careful: using 'wt' on MS Windows would introduce \r characters in the file that might not have been there before.
Stephen23
2018-2-8
@Walter Roberson: the original question uses the t option for both reading and writing, so presumably this is not a problem.
更多回答（1 个）
Walter Roberson
2018-2-8
编辑：Walter Roberson
2018-2-8
%read the file _and_ do the work of deleting extra empty lines.
new_text = regexprep( fileread(outFile), '(\r?\n)(\r?\n)+', '$1');
%write the result to a new file
fid = fopen('text_new.txt', 'w');
fwrite(fid, new_text);
fclose(fid)
3 个评论
Walter Roberson
2018-2-8
new_text = regexprep( fileread(outFile), '(\r?\n\r?\n)(\r?\n)+', '$1');
类别
在 帮助中心 和 File Exchange 中查找有关 Debugging and Analysis 的更多信息
Translated by 
