How to read .csv file using textscan function ?

Hello guys,

I have a csv file which is attached.

I have use following code to read this but i got the error.

fbc = fopen('BC100118.CSV');
BC = textscan(fbc, '%.f-%.s-%.f,%.f:%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f,%.f');
fclose(fbc);

In this file some data also lost and that is not randomly.

I want to plot data with time.

So please help ...

Answer 1

[Stephen23]

opt = {'Delimiter',',','CollectOutput',true,'TreatAsEmpty','""'};
fmt = repmat('%f',1,50);
fmt = ['%q%q',fmt];
[fid,msg] = fopen('BC100118.CSV','rt');
assert(fid>=3,msg)
C = textscan(fid,fmt,opt{:});
fclose(fid);

And checking the imported data:

>> size(C{1}) % first two columns (date/time)
ans =
   708     2
>> size(C{2}) % remaining columns (numeric)
ans =
   708    50
>> C{1}(1:7,:) % first seven rows of date/time
ans =
    '01-oct-18'    '00:00'
    '01-oct-18'    '00:02'
    '01-oct-18'    '00:04'
    '01-oct-18'    '00:06'
    '01-oct-18'    '00:08'
    '01-oct-18'    '00:10'
    '01-oct-18'    '00:12'
>> C{2}(1:7,1:7) % first seven rows of first seven columns of numeric data
ans =
   24601   26066   25801   26824   27751   28098   28102
   24467   25951   25514   26484   27156   27622   27792
   24257   25735   25431   26598   27705   28187   28310
   24177   26080   25734   26721   27502   28588   28673
   24019   25793   25450   26574   27462   27791   27769
   23723   25349   25000   26088   26620   27356   27247
   22867   24538   24292   25299   26234   26885   27176

>> C{2}(1:7,44:50) % last seven columns
ans =

   42.702    0.0212    0.8107    0.0212    2.0430    1   39.452
   44.606    0.0212    0.7964    0.0212    2.0420    1   41.230
   46.556    0.0212    0.7826    0.0212    2.0424    1   43.046
   48.523    0.0212    0.7689    0.0212    2.0428    1   44.877
   50.439    0.0212    0.7553    0.0212    2.0417    1   46.653
   52.325    0.0212    0.7425    0.0212    2.0413    1   48.395
   54.177    0.0212    0.7303    0.0212    2.0417    1   50.132

[Vishnu Dhakad]

Thanks for the information.

I have tried to plot time and numeric data but time is char type and numeric column is double type. So i got error.

Can you tell me how to plot them ??

How to convert time char into double ??

[Stephen23]

@Vishu Dhakad: what MATLAB version are you using?

[Vishnu Dhakad]

R2017a

[Stephen23]

Then you can use the datetime format %D to create date-time arrays. Read the textscan help, and read the table row "Dates and time". You will probably need something like this (untested):

fmt = repmat('%f',1,50);
fmt = ['%{dd-MMM-yy}D%{HH:mm}D',fmt];

and then manipulate the datetime objects.. These you should read too:

https://www.mathworks.com/matlabcentral/answers/243206-convert-char-to-double

https://www.mathworks.com/matlabcentral/answers/411542-how-can-i-convert-one-date-and-time-from-two-colums

[Vishnu Dhakad]

Thank you for reply

But I have used following code for the plot.

thank you again..

%% saprate time and date %%
dt = C{:,1};
Date = dt(:,1);
Time = dt(:,2);
%% plot data with time %%
Q = datetime(Time,'Format','HH:mm');
plot(Q, BC880,'DatetimeTickFormat','HH:mm','LineWidth',4)

[Vishnu Dhakad]

I want to count number of break in the plot.

can you help me?

[Stephen23]

@Vishu Dhakad: how are the breaks indicated in the data: NaN values?

[Vishnu Dhakad]

Yes, NAN Value.

[Stephen23]

isnan
diff

then count the negative values:

>> V = [1,2,NaN,NaN,3,4,NaN,NaN,5,6,7,NaN,9];
>> nnz(diff([0,isnan(V),0])<0)
ans =  3

[Vishnu Dhakad]

Thank you very much

[Vishnu Dhakad]

Hi,

I have multiple files like BC100118.CSV, BC100218.CSV, BC100318.CSV,.............

How to make batch file and read it using above code.

Thank you

[Stephen23]

https://www.mathworks.com/help/matlab/import_export/process-a-sequence-of-files.html

Answer 2

[madhan ravi]

[num,txt,raw]=xlsread('yourcsv.csv');
plot(t,num)

[Vishnu Dhakad]

Thanks for your suggetion

I want to use "textscan" function.

Can you help me