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I need help plotting data from a file

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I am trying to write a code to plot the data from the mauna loa observatory, and after having previous trouble of matlab not being able to find my file, I am now getting an error on line 7 saying "Error using .
The VariableNames property must contain one name for each variable in the table."
here is my code:
% Load the data
filename = 'maunaloa_weekly.csv';
data = readtable(filename, 'ReadVariableNames', false, 'Delimiter', ',');
variableNames = {'Date', 'Values'};
% Assign variable names to the table
data.Properties.VariableNames = variableNames;
% Convert the dates to datetime format
dates = datetime(data.Date, 'Format', 'dd/MM/yyyy');
Values = data.Values;
% Create a time vector using datetime
time_vector = dates;
% Plot the data
figure;
subplot(2, 1, 1);
plot(dates, Values, 'LineWidth', 2);
title('Maunaloa Weekly Data');
xlabel('Time');
ylabel('Floating Point Values');
if i were to run this code now, there would be an error showing that they can find the file, but thats not the problem I am working on now.

Accepted Answer

Cris LaPierre
Cris LaPierre on 31 Jan 2024
Your table must have more variable names than just those you are renaming. Try this.
data.Properties.VariableNames(1:2) = variableNames;

More Answers (1)

Walter Roberson
Walter Roberson on 1 Feb 2024
The table you are reading has some number of variables that is different than 2.
There are ways to specify the range that you want to read in, or which columns of the table you want to read. For example
opts = detectImportOptions(filename, 'ReadVariableNames', false, 'Delimiter', ',');
opts.SelectedVariableNames = {'Var1', 'Var3'};
data = readtable(filename, opts);
variableNames = {'Date', 'Values'};
% Assign variable names to the table
data.Properties.VariableNames = variableNames;
If you wanted to select the first and third columns.

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