How can I extract line numbers of text data?
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Paschalis Garouniatis
on 31 Jul 2016
Edited: Paschalis Garouniatis
on 3 Aug 2016
Hello everyone. I have attached a .txt file (portion.txt) which contains a portion of my data. What I need is to create a script which will identify strings that correspond to pairs of x-y coordinates and return their line numbers. For instance, in the .txt file the first set of coordinates begins at line 3 and ends at line 138 (the number of those pairs is written above each set of coordinates, which at this case is 136). So the script should return those two numbers. Then this process should be done for the whole file. I suppose that the process can be repeated with loop since every next set of coordinates begins after 2 lines from the previous one. How can this be done? Thanks in advance.
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Accepted Answer
Azzi Abdelmalek
on 31 Jul 2016
str=[]
fid=fopen('portion.txt')
l=fgetl(fid)
while ischar(l)
str{end+1,1}=l;
l=fgetl(fid);
end
fclose(fid)
str
idx=str(cellfun(@numel,regexp(str,'[\d\.]+'))==2)
3 Comments
Azzi Abdelmalek
on 1 Aug 2016
str=[]
fid=fopen('portion.txt')
l=fgetl(fid)
while ischar(l)
str{end+1,1}=l;
l=fgetl(fid);
end
fclose(fid)
clc
str
f=regexpi(str,'[e\-\+\d\.]+')
idx=cellfun(@numel,f)
id=idx==2
ii1=strfind([0 id'],[0 1]) % Begin
ii2=strfind([id' 0],[1 0]) % End
More Answers (2)
dpb
on 31 Jul 2016
Edited: dpb
on 1 Aug 2016
fid=fopen('portion.txt','r');
i=0; % loop counter
n=[];
while ~feof(fid) % until we run out of data
i=i+1; % increment counter
n(i)=cell2mat(textscan(fid,'%d %*[^\n]',1,'headerlines',1));
d(i)=textscan(fid,'%f %f',n(i),'collectoutput',1); % read the section
fgetl(fid); % straighten out file pointer end of record
end
fid=fclose(fid); % done with file
You'll have a list of the sizes and a cell array of M sets of nx2 coordinates to do with as wish...
Running on the file here I get...having named the m-file portion.m
>> portion
>> n
n =
136 162
>> d
d =
[136x2 double] [162x2 double]
>> cumsum([[3 2+n(1:end-1)].' [2+n].']) % the start/stop positions from the lengths
ans =
3 138
141 302
>>
5 Comments
dpb
on 2 Aug 2016
No need to create a new file, simply skip the odd headerlines before getting to the portion of the file that is regular and go from there--
fid=fopen('portion.txt','r');
for i=1:7, fgetl(fid); end % skip preliminary stuff
...
From this point everything's the same excepting for the real file you'll need to add 7 to all the line numbers obtained if you're going to use them with respect to that file.
Shameer Parmar
on 1 Aug 2016
Edited: Shameer Parmar
on 1 Aug 2016
Data = textread('portion.txt', '%s', 'delimiter', '');
LineIndex = {};
count = 1;
for i=1:length(Data)
if ~isempty(strfind(Data{i},' '))
temp_line = regexp(Data{i},' ','split');
LineIndex{count,1} = ['Begin at ',num2str(i+1)];
LineIndex{count+1,1} = ['End at ',num2str(i + str2num(temp_line{1}))];
count=count+2;
end
end
Make sure that your file "portion.txt" is in current directory.
to check output just type "LineIndex"
Output:
LineIndex =
'Begin at 3'
'End at 138'
'Begin at 141'
'End at 302'
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