How to convert character cells to date?

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Kasih Ditaningtyas Sari Pratiwi
评论： Peter Perkins 2017-10-22
Hi! I am a newbie in matlab programming. I imported csv file which contain date, time and number in it. Unfortunately, date can not be imported if it is still in the date format, so I change it to character format. The dates are in Germany version. I attach the picture.
I want it to be in the date format so I try to convert it with various method available on internet. I have been trying to find how to convert it to date format since yesterday, but I found nothing. Here is my code :
finalCSVnew{:,1}=datetime(finalCSVnew{:,1},'InputFormat','dd.MM.yyyy');
I got an error "The following error occurred converting from datetime to cell: Conversion to cell from datetime is not possible."
Please help me :(. Thank you very much for your help.

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采纳的回答

KL
KL 2017-10-22
编辑：KL 2017-10-22
The image you have attached says it's a table. In that case, it's as simple as,
finalCSVnew.Date = datetime(finalCSVnew.Date,'InputFormat', 'dd.mm.yyyy');
But I also see 'Time' column on your table, I'd recommend to combine these two to form a proper datetime.
Even better idea is to change your table into a timetable. I have been mentioning this almost everyday.
https://www.mathworks.com/help/matlab/timetables.html
https://www.mathworks.com/help/matlab/matlab_prog/create-timetables.html
Import your csv file as table and then create a timetable from it .Then you can do whatever you want to do with it, like monthly mean, yearly sum, etc. For example,
data_table = readtable('yourfile.csv');
data_timetable = table2timetable(data_table);
Read this answer here: https://de.mathworks.com/matlabcentral/answers/362146-how-do-i-separate-month-day-of-the-week-and-hour-of-the-day-for-each-row-of-a-csv-time-series-file

更多回答（1 个）

Rik
Rik 2017-10-22
Cells can be tricky to work with. The problem you encountered here is that you can't batch-process cells this way, you'll need to use cellfun to do this.
Hint: as function handle you can put @(x) datetime(x,'InputFormat','dd.MM.yyyy')
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Rik
Rik 2017-10-22
If you take a look at the documentation, you will notice that you need to provide a function. Because there isn't really a function that does what you need, you need to provide your own function. You can either make a separate m-file with that function, or you can supply an anonymous function.
anon_func=@(x) datetime(x,'InputFormat','dd.MM.yyyy');
output=cellfun(anon_func,...
Another hint (although Matlab will give a sufficiently clear error if you do it wrong): look at what value UniformOutput output should have in your case.
Peter Perkins
Peter Perkins 2017-10-22
I don't think you need to call cellfun. The datetime constructor accepts a cell array of date text.

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