Why Using '%f' as formatspec for a text file containing floating numbers gives no output
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Hello everyone,
I want to read data fom a text file. Text file contains different rows and column. I used below lines of code to read the data but it returns an empty A:
fileID = fopen('Data.txt', 'r');
formatSpec = '%f';
A = fscanf(fileID, formatSpec);
Secondly, I just want values of t where lat and lon equals:
lat = 32.4876 32.4909
lon = 117.5421 117.5739
Thank you.
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채택된 답변
Walter Roberson
2021년 9월 1일
target_lats = [32.4876 32.4909];
target_lons = [117.5421 117.5739];
filename = 'https://www.mathworks.com/matlabcentral/answers/uploaded_files/726444/Data.txt';
A = readtable(filename, 'readvariablenames', true, 'VariableNamingRule', 'preserve')
mask = ismembertol(A.lat, target_lats) & ismembertol(A.lon, target_lons);
selected_t = A.t(mask)
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Walter Roberson
2021년 9월 1일
But to answer your question:
You did not skip any input lines, so your %f was trying to read starting from the very first thing in the file. But the very first thing in the file is the word 'col' which is something that cannot be read with a %f format, so MATLAB stopped reading. fscanf() only continues to read items as long as the format matches, but the word 'col' does not match %f format.
추가 답변 (1개)
KSSV
2021년 9월 1일
data = importdata('data.txt') ;
data = data.data ;
t = data(:,7) ;
x = data(:,17) ;
y = data(:,16) ;
lat = [32.4876 32.4909] ;
lon = [117.5421 117.5739] ;
t_lon = interp1(x,t,lon) ;
t_lat = interp1(y,t,lat) ;
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