How to plot 2 columns (one is population the other is years) in a linear graph

I have an excel file with 2 columns. I want to plot the data in a simple linear graph. The problem lies with the years. I keep getting the error message:"Error using plot. When table is the second input, the first input must be a valid parent."

My code is as follows:

Population = readtable('Population.xls');

% figure_1

figure

plot(years,Population,'kx-')

xlabel ('Year','FontSize',16,'FontWeight','bold','Color','b')

ylabel ('Population (Billions)','FontSize',16,'FontWeight','bold','Color','b')

title ('Linear Growth','FontSize',20,'Color')

[Dyuman Joshi]

Are 'years' and 'Population' two columns in your table? Then use dot notation -

plot(Population.years,Population.Population,'kx-')

I would suggest to give a different name to the variable you are reading the data in, to avoid confusion.

[Dionysios]

Thank you it works like a charm. Can you please help me with the title as well ? I get this error message:

Error in title (line 81)

set(h, 'String', titlestr, pvpairs{:});

[Dyuman Joshi]

It is tought to tell from such limited code. Can you post or upload your code?

And please copy-paste the full error message.

[Voss]

That's because you say 'Color' but you don't supply a color

title ('Linear Growth','FontSize',20,'Color')
%                                           ^ missing color

e.g.,

title ('Linear Growth','FontSize',20,'Color','g')

Answer 1

[Star Strider]

This is difficult without the Excel file.

Taking a wild guess:

plot(Population.years, Population.Population)

alternatively:

plot(Population{:,1}, Population{:,2})

The second is more likely to be successful.

Note the curly brackets {} to do the table addressing.

.

[Dionysios]

Hello,

I was wondering if it is possible to constrain it to 2015 ? To help further I also attach the data.

[Star Strider]

Only one year is 2015. That would plot a black ‘x’ in the centre of the axes, and nothing else.

T1 = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1284645/Population.xls')

T1 = 78×2 table
    Year    Population
    ____    __________

       1        0.3   
    1000       0.31   
    1250        0.4   
    1500        0.5   
    1750      0.791   
    1800      0.978   
    1850      1.262   
    1900       1.65   
    1910       1.75   
    1920       1.86   
    1930       2.07   
    1940        2.3   
    1950      2.536   
    1951      2.584   
    1952      2.631   
    1953      2.677   

Y_2015 = T1(T1.Year == 2015, :)

Y_2015 = 1×2 table
    Year    Population
    ____    __________

    2015      7.383   

figure
plot(Y_2015{:,1}, Y_2015{:,2}, 'kx-')
grid

If you want to plot all of them —

figure
plot(T1{:,1}, T1{:,2}, 'kx-')
grid
xlabel ('Year','FontSize',16,'FontWeight','bold','Color','b')
ylabel ('Population (Billions)','FontSize',16,'FontWeight','bold','Color','b')
title ('Linear Growth','FontSize',20,'Color','g')

.

[Dionysios]

The second graph is what I am looking for. The thing is as you can observe, years reach up to 2500. What I want is for the x-axis to stop at the very last date (2015). So, is there a way to plot all the data, but stop at 2015 instead of 2500 ?

[Voss]

xlim([0 2015])

https://www.mathworks.com/help/matlab/ref/xlim.html

[Star Strider]

Sure!

T1 = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1284645/Population.xls');

Lv = T1{:,1} <= 2015;                                                           % Years Up To & Including 2015

figure
plot(T1{Lv,1}, T1{Lv,2}, 'kx-')
grid
xlabel ('Year','FontSize',16,'FontWeight','bold','Color','b')
ylabel ('Population (Billions)','FontSize',16,'FontWeight','bold','Color','b')
title ('Linear Growth','FontSize',20,'Color','g')

.