How to make a line-plot? Time series

Hi there, simple question. This is a subset of a larger dataset. How do I make a lineplot of the schoolyear 2000 and 2002 "students" time series? It should be one plot with two lines.

Thank you.

clc;
close all;
clear all;

table_a = readtable('Data1.xlsx');

for i = 1:height(table_a)
if table_a.month(i)>=8
    schoolyear(i) = table_a.year(i) + 1;
else
    schoolyear(i) = table_a.year(i);
end
end
table_a.schoolyear = schoolyear(:)

table_a = 9×5 table
    month    day    year    students    schoolyear
    _____    ___    ____    ________    __________

      7      29     2000       12          2000   
      7      30     2000       14          2000   
      7      31     2000       13          2000   
      8       1     2001       11          2002   
      8       2     2001       17          2002   
      8       3     2001       14          2002   
      8       4     2001       10          2002   
      8       5     2001        9          2002   
      8       6     2001       16          2002   

[Les Beckham]

What did you try?

You probably need to decide what you want to plot the selected students data against. In other words, if the selected students data is to be on the y axis of the plot, what goes on the x axis?

[Macy]

I would want the date on the x-axis, and the students on the y-axis. And since this is a representation of a larger data set, I want to know how to make a plot for a select few years. So if this data set includes 365 days per year from 1990 to 2020, I want to plot for example the year 1992, 2003, and 2006 on one plot.

So I am not sure how to do that. I have not tried any thing as I am not sure how to select for the "schoolyear" that I want.

Answer 1

[Les Beckham]

Maybe this is what you are looking for. This isn't very pretty using the small sample dataset but maybe it will look better with real data.

table_a = readtable('Data1.xlsx');

% change a few of the months in 2001 to less than 8 so they are in schoolyear 2001
table_a.month(4:6) = 2:4;

% it is a good practice to preallocate before filling the vector in a loop
schoolyear = zeros(size(table_a.month)); 
for i = 1:height(table_a)
    if table_a.month(i) >= 8
        schoolyear(i) = table_a.year(i) + 1;
    else
        schoolyear(i) = table_a.year(i);
    end
end
table_a.schoolyear = schoolyear(:);
% create a datetime column to plot against (as the x axis data)
table_a.date = datetime(table_a.year, table_a.month, table_a.day)

table_a = 9×6 table
    month    day    year    students    schoolyear       date    
    _____    ___    ____    ________    __________    ___________

      7      29     2000       12          2000       29-Jul-2000
      7      30     2000       14          2000       30-Jul-2000
      7      31     2000       13          2000       31-Jul-2000
      2       1     2001       11          2001       01-Feb-2001
      3       2     2001       17          2001       02-Mar-2001
      4       3     2001       14          2001       03-Apr-2001
      8       4     2001       10          2002       04-Aug-2001
      8       5     2001        9          2002       05-Aug-2001
      8       6     2001       16          2002       06-Aug-2001

idx = (table_a.schoolyear == 2000) | (table_a.schoolyear == 2002);
plot(table_a.date(idx), table_a.students(idx), 'o'); % I think it looks better without the lines
xlabel 'Date'
ylabel 'Student count'
grid on

An alternative would be to put each selected year in a subplot or tile.

desired_schoolyears = [2000 2002];

figure
tiledlayout(numel(desired_schoolyears), 1)
for i = 1:numel(desired_schoolyears)
    nexttile
    idx = table_a.schoolyear == desired_schoolyears(i);
    plot(table_a.date(idx), table_a.students(idx));
    xlabel 'Date'
    ylabel 'Student count'
    title(sprintf('School Year %d', desired_schoolyears(i)))
    grid on
end

EDIT:

It actually might be more natural to put the subplots side-by-side and give them a common y axis scaling for easier comparison of the data.

figure
tiledlayout(1, numel(desired_schoolyears), 'TileSpacing', 'tight')
yl = zeros(numel(desired_schoolyears), 2);
for i = 1:numel(desired_schoolyears)
    nexttile
    idx = table_a.schoolyear == desired_schoolyears(i);
    plot(table_a.date(idx), table_a.students(idx));
    xlabel 'Date'
    ylabel 'Student count'
    title(sprintf('School Year %d', desired_schoolyears(i)))
    grid on
    yl(i,:) = ylim;
end
% adjust the y axis limits to match
ymin = min(yl(:,1));
ymax = max(yl(:,2));
nexttile(1)
ylim([ymin, ymax]);
nexttile(2)
ylim([ymin, ymax]);

[Macy]

Thank you @Les Beckham for taking the time to answer this question!

[Les Beckham]

You are quite welcome.

Answer 2

[Sulaymon Eshkabilov]

Here is one of the possible solution codes:

table_a = readtable('Data1.xlsx');
table_a.schoolyear = table_a.year;
table_a.schoolyear(table_a.month>=8) = table_a.year(table_a.month>=8)+1;
figure
yyaxis left
plot(1:height(table_a),table_a.students, 'bo-', 'LineWidth',2)
ylabel('# of students')
ylim([min(table_a.students)-1, max(table_a.students)+1])
yyaxis right
plot(1:height(table_a), table_a.schoolyear, 'rd--', 'LineWidth',2)
yticks([ 2000 2001 2002 ])
yticklabels({ '2000','2001','2002' })
ylim([1999 2003])
ylabel('School year')
grid on