Superimpose scatter data points on line charts in loop

Hi team. I have a simple script which takes in stock ticker from the my list and downloads histrorical data and then plots it on line chart (X axis is date, and Y axis is close price). I want to add scatter points on the dates when I bought securities. Example - If I bought stock A on 1/2/25 and 5/2/25 then I want my codes to show two dots on the line chart on these two dates. I know scatter needs second dimension so the x value will be the dates and y value should be what is there already on the line chart. I have attached a figure of what I want to achieve.

I have a list of securities (as shown in the image column "Name"), I would like to know best way to create a list for the dates that I want as scatters (as shown in image column "Purchased (scatter)"). Please advise how to create a list of dates which can have single or multiple dates for each securities (as shown in the image below). So when loop runs for security A it should then check for all dates for A and plot them as scatter before moving to security B in second iteraton. So total number of main loop iterations would be equal to number of securities I have in Name column.

My current code takes name from the list, downloads historical prices and then plots them on line chart in Loop.

Any help would be appreciated.

kind regards

Amit

[KALYAN ACHARJYA]

Could you clarify what you mean by "purchase date sheet table"? Are you looking to generate a table from purchase data, plot a graph based on it, or something else? Let me know what you need, and I'll try to help accordingly!

[Amit Patel]

Hi Kalyan. Hope below is more clear.

Stocks = ["A"; "B"; "C"]

For loop

Codes to plot A, B and C historical prices

End

So currently I have purchased stocks A, B and C. My codes fetches the historical price of these stocks and plots them Simple. I purchased stock A on three different occassions, B on 2 occassions and C on 2 occassions. I want to plot the purchase dates of these stocks as shown in my previous image. Something like this:

Stocks = ["A"; "B"; "C"]

Dates = {[x, y, z]; [x1, y1]: [x2, y2]}

For loop

Codes to plot A, B and C historical prices

Codes to add Dates for A on A plot, for B on B plot and for C on C plot

End

x, y, z = three purchase dates of stock A

x1, y1 = two purchase dates of stock B

x2, y2 = two purchase dates of stock C

Please also tell me how to construct Dates array in such a way that it will be compatible within the loop

Answer 1

[Cris LaPierre]

You just need to have your x data match the datatype used to plot your stock data.

My suggestion would be to use datatimes for both. Then it's just a matter of plotting 2 data series on the same axis, which you can do using hold.

Here's an example where the data is in a timetable and Time is a datetime.

load SimulatedStock.mat
TMW

TMW = 1000x5 timetable
       Time         Open      High      Low      Close       Volume  
    ___________    ______    ______    ______    ______    __________

    04-Sep-2012       100    102.19     98.57    100.25    7.4792e+06
    05-Sep-2012    100.15    101.05     98.45    100.43    6.5051e+06
    06-Sep-2012     100.4    102.38    100.34    101.81    6.0469e+06
    07-Sep-2012    101.74    102.37     98.97     99.51    7.2479e+06
    10-Sep-2012     99.72    101.55     98.05     98.36    5.7329e+06
    11-Sep-2012     98.48     98.66     96.63      96.9    5.7566e+06
    12-Sep-2012      96.9     99.18     96.54     96.78    6.2104e+06
    13-Sep-2012      96.9     98.79     96.52     97.57    5.2657e+06
    14-Sep-2012     97.65     98.92     96.58     97.52    5.5528e+06
    17-Sep-2012     97.35     97.52     94.51     94.69    5.8096e+06
    18-Sep-2012     94.59     95.49     92.81     93.42    6.2436e+06
    19-Sep-2012     93.36      94.7     92.78     93.26    5.5614e+06
    20-Sep-2012     93.16     95.87      92.6     95.47    6.3724e+06
    21-Sep-2012     95.52     95.68     93.15     93.73    5.1637e+06
    24-Sep-2012     93.55     95.18     92.25     92.46    7.6349e+06
    25-Sep-2012     92.57     95.54     92.26     95.49    5.7268e+06

plot(TMW.Time,TMW.High,'g-')
ind = 900:30:1000;
hold on
plot(TMW.Time(ind),TMW.High(ind),'ro','MarkerFaceColor','r')
hold off

[Amit Patel]

Thanks Cris. Hold on and off should allow me to add additional stuff to my existing plot great. however I will still need bit help on how I can declare/establish "ind" (or stock purchase dates in my case) outside the loop in one variable. That one variable will have all required dates which need to be plotted as scatter. I might have 200 stocks in the future so I need to have a variable which stores dates for scatters outside the loop.

Example:

Stocks = ["A"; "B"; "C"]

Dates = {{x, y, z}; {x1, y1}; {x2, y2}}

How can I code after Hold on that when the For loop picks stock A for plotting time series, it also picks x, y, and z. In the second iteration the For loop will pick stock B for line chart along with x1 and y1 dates as scatter. (note the total number of dates for scatters changes with each stocks, some stocksmay have 5 dates to plot, some stocks only 2 or 1).

I am struggling to construct Dates variable outside the For loop. I get your point of keeping Dates variable in the datetime format.

Once I know how to create Dates variable then all I will need to do when I purchase a new security is add that stock to variable "Stocks" and then date to variables "Dates" and the rest should be taken care by the For loop. My both variables "Stocks" and "Dates" will continue to grow in size and may look something like this in 2 years. So the codes should be written in such a way that can handle it.

Stocks = ["A"; "B"; "C", "D", "E", "F", "G"]

% total 7 securities

Dates = {{x, y, z}; {x1, y1}; {x2, y2}, {x3, y3, z3, l3, m3, a3, b3};

{x4, y4, z4, l4, m4}; {x5, y5}; {x6, y6, z6, l6, m6, a6, b6}}

% total 7 sets of cells each containns different number of dates.

"Stocks" and "Dates" will be my global variables that needs to stay outside the For loop (nt inside). Cheers.

Am I still unclear?

[Cris LaPierre]

ind was a variable I created to extract a subset of data for the purpose of plotting points. It was a shortcut approach to creating that data and is not necessarily part of the solution you need.

It's hard to give a specific answer when working with hypothetical data. Could you please share a representative data set? You can either save your variables to a mat file or a spreadhseet and attach it to your post using the paperclip icon.

[Amit Patel]

ok so I have attached my codes. Please note I have removed URL and access token from it because they are sensitive info. you will get the idea though.

When you open my codes you will notice that I am plotting stock price fin in a loop but I don't know how to properly construct Dates variable and plot them on the same plot. Server said cannot attach .docx file so I have attached .pdf file.

% Variables
Stocks = ["ITC.NSE"; "RELIANCE.NSE"; "FLEXI.NSE"; "RPOWER.NSE"];
Dates = {
    {'15/2/24', '18/11/24', '22/1/25', '1/2/25'},
    {'15/2/24', '22/1/25'},
    {'22/1/25'},
    {'18/11/24', '22/1/25', '1/2/25'}
    }

% Codes
[rows, ~] = size(Stocks);
for_start = 1;
for_end = rows;
for A = for_start : for_end
    % Construct url and download individual stock data
    URL2 = url2A + company + url2B + dt_str + url2C + token + url2D; % URL
    EOD_data = webread(URL2); % Json data
    dataStruct = jsondecode(EOD_data); % data convert
    EOD_DATA = struct2table(dataStruct); % Create a table
    EOD_DATA(:, [2, 3, 4, 5]) = []; % Drop columns
    EOD_DATA.Properties.VariableNames = ['Date', ‘Price’];
    figure;
    plot(Date, Price, 'black');
end

[Cris LaPierre]

It would also be helpful to see what the downloaded data looks like. Could you save your variable Stocks to a mat file and attach that as well?

Also, what are variables Date and Price? They are not defined in the code.you shared.

As for the dates, try this

Dates = {
    {'15/2/24', '18/11/24', '22/1/25', '1/2/25'},
    {'15/2/24', '22/1/25'},
    {'22/1/25'},
    {'18/11/24', '22/1/25', '1/2/25'}
    };

for c = 1:length(Dates)
    D = datetime(Dates{c},'InputFormat','dd/M/yy')
end

D = 1x4 datetime array
   15-Feb-2024   18-Nov-2024   22-Jan-2025   01-Feb-2025

D = 1x2 datetime array
   15-Feb-2024   22-Jan-2025

D = datetime
   22-Jan-2025

D = 1x3 datetime array
   18-Nov-2024   22-Jan-2025   01-Feb-2025

[Cris LaPierre]

You can also convert your date strings to datetimes with cellfun (avoids using a for loop if that is desirable).

Dates = {
    {'15/2/24', '18/11/24', '22/1/25', '1/2/25'},
    {'15/2/24', '22/1/25'},
    {'22/1/25'},
    {'18/11/24', '22/1/25', '1/2/25'}
    };

D = cellfun(@(x) datetime(x,'InputFormat','dd/M/yy'),Dates,'UniformOutput',false)

D = 4x1 cell array
    {[15-Feb-2024    18-Nov-2024    22-Jan-2025    01-Feb-2025]}
    {[15-Feb-2024    22-Jan-2025                              ]}
    {[22-Jan-2025                                             ]}
    {[18-Nov-2024    22-Jan-2025    01-Feb-2025               ]}

[Amit Patel]

Thank you very much Cris, I think your codes for D will solve my problem. You guys are awesome... Cheers.