I have a .txt file with over 100,000 rows, want to extract rows that have two specific numbers (latitude and longitude) and save it in Ms Excel.

I have a very large .txt file with over a 100,000 rows.

I want to extract rows (from the .txt file) that have a specific latitude and longitude and save the extracted rows in Excel.

I currenlty have this code but when I run it I get an error : unexpected MATLAB expression (in the first line of code)

function PET('text_file', num1, num2);

% Open the text file in read mode

fid = fopen(data_2018.txt, 'r');

% Create a new Excel file

excel_file = [data_2018.txt '.xlsx'];

xlswrite(excel_file, []);

% Iterate through the lines in the text file

while ~feof(fid)

% Read the current line

line = fgetl(fid);

% Split the line into a cell array

line_array = strsplit(line, ' ');

% Check if the line contains the two specified numbers

if ismember(27.249, line_array) && ismember(-82.380, line_array)

% Copy the line to the Excel file

xlswrite(excel_file, line);

end

end

% Close the text file

fclose(fid);

end

[Dyuman Joshi]

In the definition of a function, the input arguements to the function are supposed to be variables (placeholders) and not values (char or otherwise).

%            vvvvvvvvvvv 
function PET('text_file', num1, num2);

Apart from this your code has many errors (for the lack of better word) -

1 - It's not clear to me why you have defined input arguements, when your code doesn't use them.

2 - You are supposed to use string or char vector as input to fopen

3 - I don't understand what this line is supposed to do. Possible concatenation to make a string, but then the implementation is questionable.

excel_file = [data_2018.txt '.xlsx'];

4 - If the variable line_array is a cell array, how are you going to compare a numeric value to it?

% Split the line into a cell array
line_array = strsplit(line, ' ');
% Check if the line contains the two specified numbers
if ismember(27.249, line_array) && ismember(-82.380, line_array)

Also, Use of xlswrite is not recommended, you should instead use writematrix (or writetable)

[Leslie]

Thank you for the comments

Answer 1

[Pratyush]

Hi Leslie,

I understand that you have a text file with multiple lines in which some lines contains a particular pair of number(latitude, longitude) written in between. You want to extract those lines in a row of some Excel sheet. This could be done using the following lines in MATLAB.

% form an array of lines from your text file

fileContent = fileread('your_file.txt');

lines = splitlines(fileContent);

latitude = 42;

longitude = 73;

matchingLines = {};

% iterate through lines and add the desired line to matching line

for i = 1:numel(lines)

line = lines{i};

% ensure the order of latitude and longitude

% because (lat,lon) isn't same as (lon, lat)

pattern = sprintf('%d.*%d', latitude, longitude);

if ~isempty(regexp(line, pattern, 'once'))

matchingLines{end+1, 1} = line;

end

end

% write matchingLines to excel sheet

xlswrite('extracted_data.xlsx', matchingLines, 'Sheet1', 'A1');

[Leslie]

I really appreciate your assistance.

Thank you