How to extract the following number from a text file?

Question

Ahmad Fakih 2019-4-23

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/458051-how-to-extract-the-following-number-from-a-text-file

评论： Walter Roberson 2019-4-24

采纳的回答： Bob Thompson

output_matlab.txt

Dear memebers,

Can you please help me extract the following number hilighted in yellow from a text file into MATLAB?

The numbers will change each time but other characters will stay the same.

You can find the text file attached and that number will be at the end of the text.

Thank you!

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Answer 1

Bob Thompson 2019-4-23

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https://ww2.mathworks.cn/matlabcentral/answers/458051-how-to-extract-the-following-number-from-a-text-file#answer_371898

There are a couple of options how to do this. You can read the entire file in as strings, find the line you want, and regexp the numbers from the line, or you can choose to search through the entire thing by each line with fgetl, and look for a match, then extract the number based on the position of the numbers. Below are two examples, they will need some tweaking if you plan to use them.

% Regexp method
text = fileread('mypath\output_matlab.txt');
number = regexp(text,'Pile-head deflection\s+.\s+(\d.\d+) meters','tokens');
% fgetl method
fid = fopen('mypath\output_matlab.txt');
line = fgetl(fid);
count = 1;
while ~isnumeric(line)
    if strcmp(line(1:9),'Pile-head')
        number = str2num(line(30:40));
        break
    else
        line = fgetl(fid);
        count = count + 1;
    end
end

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Bob Thompson 2019-4-24

Extracting from a cell is simple enough if you just specify a variable as the contents of the cell.

number = number{1};

Sometimes you may have to go a couple of levels deep, because regexp is silly about that. Just do {1}{1} if needed.

Ahmad Fakih 2019-4-24

Yeah a couple of them worked, thanks!

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Answer 2

Walter Roberson 2019-4-23

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/458051-how-to-extract-the-following-number-from-a-text-file#answer_371897

编辑：Walter Roberson 2019-4-24

在 MATLAB Online 中打开

filename = 'output_matlab.txt';
S = fileread(filename);
phd_str = regexp(S, '(?<=^Pile-head deflection\s+=\s+)\S+', 'match', 'lineanchors');
phd = str2double(phd_str);

This code will find any Pile-head deflection value that is in the file. If you are sure that there is only one in the file, then you can add the option 'once' to the regexp() call to speed up execution.