Extract or import two Specific values form Text file - MATLAB

Question

I am working on a problem in MATLAB, in which I need to import two specific values (highlighted) from a text file as shown in the figure 1.

Corresponding .txt file is attached in the following link (Link)

amahmud · Answer 1 · 2018-07-24T06:29:59.150

0

Hopefully this will work.

delimiter = ' ';
startRow = 7;
fileID = fopen(filename,'r');     
formatSpec = '%f%f%[^\n\r]';
dataArray = textscan(fileID, formatSpec,startRow-startRow+1, 'Delimiter', delimiter, 'HeaderLines' ,startRow-1, 'ReturnOnError', false,'MultipleDelimsAsOne',1, 'EndOfLine', '\r\n');
val1 = dataArray{1,1};
val2 = dataArray{1,2};

edited Jul 24 '18 at 06:29

answered Jul 24 '18 at 05:09

amahmud

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4
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Thank you very much, the code is not working. It is starting at 7th row but, dataArray is giving me a combination of doubles and cells, I am unable to extract two values specifically – The_Learner Jul 24 '18 at 05:36
I think there's need to be some modification. Can you upload the data in the question? Just remove the image and put the actual texts from the .txt file. – amahmud Jul 24 '18 at 05:44
text file attached, please find – The_Learner Jul 24 '18 at 05:53

Paolo · Accepted Answer · 2018-07-24T10:09:58.443

When you want to extract specific values from a text file you should always consider using regular expressions.

For getting the two values you highlighted you can use:

raw = fileread('M7_soil_FN_1.txt');
val = regexp(raw,'(\d+)\s+(\d+\.\d+)\s+(?=NPTS)','tokens')

The regular expression says:

(\d+) Match digits and capture.
\s+ Match whitespace.
(\d+\.\d+) Match and capture digits, a full stop, more digits.
\s+ Match whitespace.
(?=NPTS) Positive lookahead to ensure that what follows is NPTS.

Then convert val to double:

val = str2double(val{:})
>>val(1)

    5991

>>val(2)

    0.0050

If you are interested, you can see the regular expression in action live here.

Extract or import two Specific values form Text file - MATLAB

2 Answers2