MATLAB: Using Datenum to convert YYYY MM DD HH

datenumdatesembedded matlab functionmatrix arraymonthsyears

I have an 8219×6 matrix containing YYYY MM DD HH Wind_Speed Wind_Dir

I am trying to convert the first 4 columns using datenum using the code:

dNum = datenum([nineteen_49(:,1) nineteen_49(:,2) nineteen_49(:,3) nineteen_49(:,4) zeros(length(nineteen_49(:,4))) zeros(length(nineteen_49(:,4)))]);

But this isnt working as it is returning an 8219×16422 matrix instead of 8219×6. Not sure what the problem is?

Best Answer

dNum = datenum([nineteen_49(:,1:4) zeros(length(nineteen_49),2)]);

You missed the second argument to zeros in your augmentation and append two square matrices of 8219x8219 instead of two vectors of length 8219. I'm a little surprised datenum didn't error on the size of the vector 2nd dimension altho I suppose it took it as an extremely precise number of fractions of seconds after the minute, seconds and fractional seconds fields.

Related Solutions

MATLAB: I am new to Matlab and I am trying to use some codes which generate some errors. Please help me to correct the following errors: Error: File: sampleStats.m Line: 31 Column: 64 Expression or statement is incorrect–possibly unbalanced (, {, or [.

The lines

   msg = cell2mat ( strcat ('Lacking sufficient data in ' ,{' '},
  filename ;', data avaliable for period ’ ,{' '}, datestr ( date (1)) ,{'
  - '}, datestr ( date ( length ( date )))));

need to be written all as one line, or you need to use the ... continuation marker.

   msg = cell2mat ( strcat ('Lacking sufficient data in ' ,{' '}, filename ;', data avaliable for period ’ ,{' '}, datestr ( date (1)) ,{'  - '}, datestr ( date ( length ( date )))));

Also, you cannot use semi-colon at that point, as you are not within [] .

Furthermore, if you look very carefully at the character after "for period" it is ’ which is char(8217) which is Right Single Quotation, where you need ' instead.

Putting these together, you get

   msg = cell2mat ( strcat ('Lacking sufficient data in ' ,{' '}, filename ,', data available for period ' ,{' '}, datestr ( date (1)) ,{'  - '}, datestr ( date ( length ( date )))));

MATLAB: Datetime with variable format

Unfortunatelly you cannot specify multiple InputFormats simultaneously. Common to Name-Value pairs is that the last instance of a name value pair is used; in your example this is: 'yyyy-MM-dd HH:mm:ss'. One thing you can do to work around this issue is to convert the cell string to a vector of MATALB Serial Date Numbers and then to a datetime:

d = datenum(a);
d = datetime(d,'Format','yyyy-MM-dd HH:mm:ss.S','convertFrom','datenum');

I would caution you here as if you attempt to change the format in the line d = datenum(a) you will error due to a non-conforming entry.

Best Answer

Related Solutions

MATLAB: I am new to Matlab and I am trying to use some codes which generate some errors. Please help me to correct the following errors: Error: File: sampleStats.m Line: 31 Column: 64 Expression or statement is incorrect–possibly unbalanced (, {, or [.

MATLAB: Datetime with variable format

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