Why won't Matlab recognize my data?

2022 4 15
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更新时间：2022 4 15
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I am trying to plot CSV data (attached) on Google search trends, but the date (year and month) is only appearing as "NaN." How do I plot this?

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Voss
Voss 2022-4-15
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The answer depends on how you're reading the file and how you want to deal with the cells in column 2 that say "<1".
One way to do it using readtable:
T = readtable('multiTimeline.csv')
Warning: Column headers from the file were modified to make them valid MATLAB identifiers before creating variable names for the table. The original column headers are saved in the VariableDescriptions property.
Set 'VariableNamingRule' to 'preserve' to use the original column headers as table variable names.
T = 220×2 table
Month universalBasicIncome__UnitedStates_ ___________ ___________________________________ {'2004-01'} 5 {'2004-02'} 0 {'2004-03'} 0 {'2004-04'} 0 {'2004-05'} 0 {'2004-06'} 5 {'2004-07'} 0 {'2004-08'} 0 {'2004-09'} 0 {'2004-10'} 0 {'2004-11'} 0 {'2004-12'} 0 {'2005-01'} 0 {'2005-02'} 3 {'2005-03'} 0 {'2005-04'} 0
plot(datetime(T.Month,'InputFormat','yyyy-MM'),T.universalBasicIncome__UnitedStates_)
One way to do it using readcell:
C = readcell('multiTimeline.csv')
C = 222×2 cell array
{'Category: All categories'} {1×1 missing } {'Month' } {'universal basic income: (United States)'} {'2004-01' } {[ 5]} {'2004-02' } {[ 0]} {'2004-03' } {[ 0]} {'2004-04' } {[ 0]} {'2004-05' } {[ 0]} {'2004-06' } {[ 5]} {'2004-07' } {[ 0]} {'2004-08' } {[ 0]} {'2004-09' } {[ 0]} {'2004-10' } {[ 0]} {'2004-11' } {[ 0]} {'2004-12' } {[ 0]} {'2005-01' } {[ 0]} {'2005-02' } {[ 3]}
C([1 2],:) = []; % remove header rows
idx = ~cellfun(@isnumeric,C(:,2)); % replace "<1" or any other
C(idx,2) = {NaN}; % non-numeric entry with a NaN
plot(datetime(C(:,1),'InputFormat','yyyy-MM'),vertcat(C{:,2}));
There are other ways.

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Walter Roberson
Walter Roberson 2022-4-15
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filename = 'https://www.mathworks.com/matlabcentral/answers/uploaded_files/965680/multiTimeline.csv';
opt = detectImportOptions(filename, 'PreserveVariableNames', true);
opt = setvartype(opt, 1, 'datetime');
opt = setvaropts(opt, 1, 'InputFormat', 'yyyy-MM');
T = readtable(filename, opt);
T(1:2,:)
ans = 2×2 table
Month universal basic income: (United States) _______ _______________________________________ 2004-01 5 2004-02 0

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econogist
econogist 2022-4-15
This is great, but how do I plot?
Walter Roberson
Walter Roberson 2022-4-15
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filename = 'https://www.mathworks.com/matlabcentral/answers/uploaded_files/965680/multiTimeline.csv';
opt = detectImportOptions(filename, 'PreserveVariableNames', true);
opt = setvartype(opt, 1, 'datetime');
opt = setvaropts(opt, 1, 'InputFormat', 'yyyy-MM');
T = readtable(filename, opt);
plot(T{:,1}, T{:,2})

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