Undefined variable or class error

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Denk 2019-3-19

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评论： Denk 2019-3-19

NEWSST_2015.mat

The variable "NEWSST_2015" is not defined properly it seems, probably has to do with how time is indexed.. Could you please suggest how to index time here? The .mat file used is attached.

%% convert from daily to weekly (8-day) averages
load NEWSST_2015.mat
% Convert data into timetable
NEWSST_2015 = datetime(NEWSST_2015); 
NEWSST_2015 = table2timetable(NEWSST_2015);
% Create time vector (8-day duration)
t = NEWSST_2015(1);
startTime = datetime(t.Year,t.Month,t.Day,t.Hour,0,0);
time = (startTime:days(8):NEWSST_2015(end))';
% Resampling
NEWSST_2015_2 = retime(NEWSST_2015,time,'linear');

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Answer 1

Adam 2019-3-19

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编辑：Adam 2019-3-19

在 MATLAB Online 中打开

The variable in your mat file is called NEWSST, not NEWSST_2015.

It is usually better though to load a mat file into a struct and then reference from that e.g.

loadedData = load( 'NEWSST_2015.mat' );
NEWSST_2015 = loadedData.NEWSST;

then you will have a variable of the name you use. I haven't checked if the rest of your code is fine, but the variable not existing is certainly the main problem.

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Denk 2019-3-19

在 MATLAB Online 中打开

Good point about NEWSST.

I have implemented it like this though and run it:

%% convert from daily to weekly (8 day) averages
loadedData = load( 'NEWSST_2015.mat' );
NEWSST_2015 = loadedData.NEWSST; % Convert data into timetable
NEWSST_2015 = datetime(NEWSST_2015); 
NEWSST_2015 = table2timetable(NEWSST_2015);  % turn table into a timetable 
% Create time vector (8-day duration)
t = NEWSST_2015(1);
startTime = datetime(t.Year,t.Month,t.Day,t.Hour,0,0);
time = (startTime:days(8):NEWSST_2015(end))';
% Resampling
NEWSST_wavg = retime(NEWSST_2015,time,'linear');

and now i get these consecutive errors:

Error using datetime (line 588)

Numeric input data must be a matrix with three or six columns, or else three, six, or seven separate numeric arrays. You can also create datetimes from a single numeric array using the 'ConvertFrom' parameter.

Error in sst_test (line 31)

NEWSST_2015 = datetime(NEWSST_2015);

Error using table2timetable (line 43)

First argument must be a table.

Error in sst_test (line 32)

NEWSST_2015 = table2timetable(NEWSST_2015); % turn table into a timetable

Error using datetime (line 588)

Numeric input data must be a matrix with three or six columns, or else three, six, or seven separate numeric arrays. You can also create datetimes from a single numeric array using the 'ConvertFrom' parameter.

Error in sst_test (line 32)

NEWSST = datetime(NEWSST);

Pretty confused !

Adam 2019-3-19

I don't use datetime, but the error message seems very clear in what it expects. You give it a 3-dimensional array which does not conform in any way to those expectations.

Denk 2019-3-19

Thank you for your comments and time.

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