Table to timetable but the datetime doesn't like my data

Hello

I'm trying to convert my data into a timetable. It seems simple and straightforward but sill it doesn't work. This is the code:

NAO = readtable('NAOdaily.txt')

% Extract columns for datetime creation
year = NAO(:, 1);
month = NAO(:, 2);
day = NAO(:, 3);

% Create a datetime array
dateArray = datetime(year, month, day);

% Extract the remaining columns
values = NAO(:, 4);

% Create timetable
NAOTT = timetable(dateArray, values, 'VariableNames', {'Date', 'Value'});

Can you let me know at what point have I missed something? I'm attaching my txt file too.

Error using datetime
Invalid parameter name. Parameter name must be a nonempty string or character vector.

Error in LoadNAODaily (line 9)
dateArray = datetime(year, month, day);

Adding these didn't make a difference

dateArray = datetime('year', 'month', 'day');

Thanks for any assistance

[Dyuman Joshi]

If you are using R2019a or a newer version, use readmatrix to directly read the data as a matrix.

NAO = readmatrix('NAOdaily.txt');

% Extract columns for datetime creation
year = NAO(:, 1);
month = NAO(:, 2);
day = NAO(:, 3);

% Create a datetime array
dateArray = datetime(year, month, day);
% Extract the remaining columns
values = NAO(:, 4);

% Create timetable
NAOTT = timetable(dateArray, values)

NAOTT = 27733×1 timetable
     dateArray     values
    ___________    ______

    01-Jan-1948    -87.04
    02-Jan-1948    -72.39
    03-Jan-1948    -60.47
    04-Jan-1948       -62
    05-Jan-1948    -36.48
    06-Jan-1948    -25.51
    07-Jan-1948    -30.01
    08-Jan-1948    -42.51
    09-Jan-1948    -66.63
    10-Jan-1948    -84.36
    11-Jan-1948    -55.47
    12-Jan-1948     11.01
    13-Jan-1948     34.05
    14-Jan-1948     34.89
    15-Jan-1948     50.19
    16-Jan-1948     89.74

[OcDrive]

Thanks for the advice Dyuman, that's certainly an easier way of doing that

Answer 1

[Hassaan]

The correct way to create a datetime object in MATLAB from separate year, month, and day columns is to ensure that these columns are extracted as numeric arrays, not as table variables. When you read the data using readtable, you should use the specific column names or indices. Since your text file doesn't have headers, you would use indices like NAO{:, 1} to get the data.

NAO = readtable('NAOdaily.txt', 'Format', '%d %d %d %f');  % Specify the format of the data

% Extract columns for datetime creation
year = NAO{:, 1};
month = NAO{:, 2};
day = NAO{:, 3};

% Create a datetime array
dateArray = datetime(year, month, day);

% Extract the values column and ensure it's a vector
values = NAO{:, 4};

% Create timetable
NAOTT = timetable(dateArray, values);

head(NAOTT, 5)

Output

dateArray values

___________ ______

01-Jan-1948 -87.04

02-Jan-1948 -72.39

03-Jan-1948 -60.47

04-Jan-1948 -62

05-Jan-1948 -36.48

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[OcDrive]

Thanks Muhammad