Unable to perform assignment because dot indexing is not supported for variables of this type.

RiskFree = readtable("DTB3.csv", 'TreatAsEmpty',{'.','NA'});
RiskFree = rmmissing(RiskFree);
 
% Extract Data / Select only the period going from 01-10-2015
Data0 = RiskFree{1389:end,2};                                             
date0 = RiskFree{1389:end,1};                                             
 
% Standardize the date format to match the one of sector indices
datetime.setDefaultFormats('defaultdate','dd-MMM-yyyy');
date0.Format = 'defaultdate';

I get "Unable to perform assignment because dot indexing is not supported for variables of this type."

What should I do?

[Steven Lord]

On which line did you receive this error?

What is the class of date0?

Which release of MATLAB are you using?

[Julien Rivier]

The following line: "date0.Format = 'defaultdate'"

The class is: 1115x1 cell (it comes from a csv file)

I am using the Student License / R2019b Update 4 / 64-bit (maci64)

Thanks!

[Image Analyst]

AFTER you read this link, attach your CSV file so people can try things. But date0 is not a class or a structure. What does this say:

whos date0

and don't forget to attach the CSV file.

[Julien Rivier]

I attached here the csv file.

This is what I get when running whos date0:

Name Size Bytes Class Attributes

date0 1115x1 142720 cell

Thanks

Answer 1

[Guillaume]

The error is easily explained. You're expecting readtable to read the first column of your csv as a datetime. You haven't checked that it does and it turns out that it doesn't (because it's not obvious to matlab that it is a date). It reads the column as text so date0 ends up as a cell array.

One way to force matlab to read the column as date:

opts = detectImportOptions('DTB3.csv'); 
opts = opts.setvaropts('DATE', 'Type', 'datetime', 'InputFormat', 'dd.MM.yy', 'DatetimeFormat', 'dd MMM yyyy');
RiskFree = readtable('DTB3.csv', opts);

Note that the way the date is encoded in your file is ambiguous. If you can, change whatever creates these files so that it encodes the year with 4 digits.