Read a file with textscan.
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I have a text file that I'm trying to read with textscan. The top of my file looks like
######################################################################
Test File Name: MNTFEPLANC-122-202203171547
Timestamp: 202203171547
Test Type: FILL Valve Selction: BOTH Valve Cycle Time: 2
######################################################################
20220317154734, 0.0, 0.0, 0.0, 0.0,17714,17449,20464,17041,17028, 0.000000,0.000000,0.000000
20220317154734, 0.0, 0.0, 0.0, 0.0,17714,17449,20464,17041,17028, 0.000000,0.000000,0.000000
20220317154734, 0.0, 0.0, 0.0, 0.0,17714,17449,20464,17041,17028, 0.000000,0.000000,0.000000
20220317154734, 0.0, 0.0, 0.0, 0.0,17714,17449,20464,17041,17028, 0.000000,0.000000,0.000000
20220317154734, 0.0, 0.0, 0.0, 0.0,17714,17449,20464,17041,17028, 0.000000,0.000000,0.000000
20220317154734, 0.0, 0.0, 0.0, 0.0,17714,17449,20464,17041,17028, 0.000000,0.000000,0.000000
20220317154734, 0.0, 0.0, 0.0, 0.0,17714,17449,20464,17041,17028, 0.000000,0.000000,0.000000
20220317154734, 0.0, 0.0, 0.0, 0.0,17714,17449,20464,17041,17028, 0.000000,0.000000,0.000000
I open the file using
raw_data_file = fopen(file_name,'rt') % The full path of "file_name" has been ommitted for brevity.
which yields
raw_data_file =
17
I read the file using
fe_data_read = textscan(raw_data_file,'%f%f%f%f%f%f%f%f%f%f%f%f%f','Delimiter',',');
which yields
fe_data_read =
1×13 cell array
Columns 1 through 10
{0×1 double} {0×1 double} {0×1 double} {0×1 double} {0×1 double} {0×1 double} {0×1 double} {0×1 double} {0×1 double} {0×1 double}
Columns 11 through 13
{0×1 double} {0×1 double} {0×1 double}
I tried to create a variable with values being the first column using
test_date_time = fe_data_read{1}
which yields
test_date_time =
0×1 empty double column vector
Why is "test_date_time" not being populated with the values in the first column of my text file? What am I doing wrong?
Answers (2)
The file starts with this line:
######################################################################
This does not match the format string '%f%f%f%f%f%f%f%f%f%f%f%f%f' or the Delimiter=',' in any way. Therefore textscan replies an empty output.
You have to tell textscan, that the first 6 lines are a header and have to be skipped. Use the 'Headerlines" argument.
By the wya, do you have a reason to open the file in the slower text mode?
5 Comments
Allen Hammack
on 26 Mar 2022
Allen Hammack
on 28 Mar 2022
Stephen23
on 28 Mar 2022
"The problem I'm running into seems to be related to the carriage returns in my input file, which aren't translated when I copied a section of my input file in my original question."
@Allen Hammack: If you want us to check your original file, then you need to provide us with your original file.
Please upload your original file by clicking the paperclip button.
Allen Hammack
on 28 Mar 2022
That file has a mix of newline characters, but Walter Roberson's code imports it without any problems:
fnm = 'orig_data_trim.txt';
opt = detectImportOptions(fnm, 'HeaderLines', 6);
opt = setvartype(opt, 1, 'datetime');
opt = setvaropts(opt, 1, 'InputFormat', 'uuuuMMddHHmmss');
T = readtable(fnm, opt)
opt = {'Delimiter',',','Headerlines',6,'CollectOutput',true};
fmt = ['%{uuuuMMddHHmmss}D',repmat('%f',1,12)];
fid = fopen('new.txt','rt');
tmp = textscan(fid,fmt,opt{:});
fclose(fid);
tmp{1}
tmp{2}
1 Comment
filename = 'https://www.mathworks.com/matlabcentral/answers/uploaded_files/941499/new.txt';
opt = detectImportOptions(filename, 'HeaderLines', 6);
opt = setvartype(opt, 1, 'datetime');
opt = setvaropts(opt, 1, 'InputFormat', 'uuuuMMddHHmmss');
T = readtable(filename, opt)
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