Wrong date while importing .csv
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Having a problem when i import daily .csv files. More specifically, when i plot my xy data(x axis contains date and time stamp), in every different daily file, MATLAB shows todays date. Any ideas?
4 个评论
madhan ravi
2018-8-24
Upload your file by clicking the paper clip button.
madhan ravi
2018-8-24
can you upload your code?
madhan ravi
2018-8-24
Just lookup xticklabels.
@Sirius8: this is what one line of the file looks like:
00:00:0;0.0;0.00540500736377
Where is the date? Please show us which parts of that line contain date data.
采纳的回答
The date is not automatically assigned because it's not in the data but in the name of the file. You could do something like this:
files=dir('folderpath~\*.csv');
for i=1:length({files.name})
date=files(i).name;
date=regexprep(date,'.csv','')
data=readtable(files(i).name);
t{i}=data{:,1}+datetime(date);
xy{i}=data{:,2:3}
end
Now you have two cell arrays, t and xy, where the former has all time data and the latter all other data.
8 个评论
jonas
2018-8-24
It seems your local settings are different from mine, so readtable interprets the first column as datetime instead of duration. Add these two lines at the beginning of the loop.
opts=detectImportOptions(files(i).name)
opts=setvartype(opts,'Var1','duration')
I'm having trouble reproducing the issue. At what line does it say that?
type this and paste the output in comment here:
varfun(@class,data,'OutputFormat','cell')
Alright, what release are you running? We may have to convert the cell to duration subsequent to loading the table. Copy a few rows from the first column here so I can figure out how to convert it. In the meantime, you can try:
TT=timetable(data)
as timetable is sometimes smart enough to figure out the format of the input.
Let's skip readtable altogether and try another import option:
files=dir('folderpath~\*.csv');
for i=1:length({files.name})
date=files(i).name;
date=regexprep(date,'.csv','')
din=importdata(files(i).name,';')
t{i}=duration(din.textdata,'format','hh:mm:ss')+datetime(date);
xy{i}=din.data
end
I wouldn't recommend your other solution. Albeit it could work, it is the opposite of robust.
jonas
2018-8-24
Seems to have been more updates to DURATION than I was aware of but alright, give me a few minutes to fix
Walter Roberson
2018-8-24
In this situation, let it be imported as datetime, but then do
t{i} = data.Var1 - dateshift(data.Var1, 'start', 'day') + datetime(day);
Thanks Walter, that should do the trick.
If it, for some reason, still does not work. Then this solution should. It's however much slower due to the cellfun
files=dir('folderpath~\*.csv');
for i=1:length({files.name})
date=files(i).name;
date=regexprep(date,'.csv','')
din=importdata(files(i).name,';')
tday=cellfun(@(x) str2double(strsplit(x,':')),din.textdata,'uniformoutput',false)
tday=cell2mat(tday);
t{i}=hours(tday(:,1))+minutes(tday(:,2))+seconds(tday(:,3))+datetime(date);
xy{i}=din.data
end
The absolute best solution would be to update MATLAB :)
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