Dot indexing is not supported for variables of this type.

I may have explained it wrong in my previous question. I will send you the full code and then I will throw out the errors I get. I would be very happy if you solve it.

fetchFiveDayForecast.m :

function weatherData = fetchFiveDayForecast(city, apiKey)

baseUrl = 'https://api.openweathermap.org/data/2.5/forecast';

url = sprintf('%s?q=%s&appid=%s&units=metric', baseUrl, city, apiKey);

response = webread(url);

% Process JSON data

if isfield(response, 'list')

list = response.list;

else

error('Invalid response structure');

end

% Initialize data struct

data = struct();

numEntries = length(list);

% Loop through each entry in the list and extract data

for i = 1:numEntries

data(i).dt = datetime(list(i).dt_txt, 'InputFormat', 'yyyy-MM-dd HH:mm:ss', 'Format', 'yyyy-MM-dd HH:mm:ss', 'TimeZone', 'UTC');

data(i).temp = list(i).main.temp;

data(i).humidity = list(i).main.humidity;

data(i).windSpeed = list(i).wind.speed;

end

% Store the data in the output structure

weatherData = struct();

weatherData.dt = [data.dt];

weatherData.temp = [data.temp];

weatherData.humidity = [data.humidity];

weatherData.windSpeed = [data.windSpeed];

end

app2.mlapp :

classdef app2 < matlab.apps.AppBase

% Properties that correspond to app components

properties (Access = public)

UIFigure matlab.ui.Figure

GetInfoButton matlab.ui.control.Button

AddCityButton matlab.ui.control.Button

CityEditField matlab.ui.control.EditField

CityEditFieldLabel matlab.ui.control.Label

CityDropDown matlab.ui.control.DropDown

CityDropDownLabel matlab.ui.control.Label

UIAxes3 matlab.ui.control.UIAxes

UIAxes2 matlab.ui.control.UIAxes

UIAxes matlab.ui.control.UIAxes

end

properties (Access = private)

apiKey = '8837203c2a21882aa541f6d408e564ab'; % Gerçek API anahtarınız ile değiştirin

cities = {'Adana' , 'Ankara' , 'İstanbul' , 'Antalya'}; % Şehirler için boş bir hücre dizisi başlatın

end

methods (Access = private)

function updateWeatherData(app,~)

selectedCity = app.CityDropDown.Value;

weatherData = fetchFiveDayForecast(selectedCity, app.apiKey);

% Update Temperature Plot

plot(app.UIAxes, weatherData.dt, weatherData.temp, '-o');

title(app.UIAxes, 'Temperature (°C)');

xlabel(app.UIAxes, 'Date and Time');

ylabel(app.UIAxes, 'Temperature (°C)');

% Update Humidity Plot

plot(app.UIAxes2, weatherData.dt, weatherData.humidity, '-o');

title(app.UIAxes2, 'Humidity (%)');

xlabel(app.UIAxes2, 'Date and Time');

ylabel(app.UIAxes2, 'Humidity (%)');

% Update Wind Speed Plot

plot(app.UIAxes3, weatherData.dt, weatherData.windSpeed, '-o');

title(app.UIAxes3, 'Wind Speed (m/s)');

xlabel(app.UIAxes3, 'Date and Time');

ylabel(app.UIAxes3, 'Wind Speed (m/s)');

end

function addCity(app)

newCity = app.CityEditField.Value;

if ~any(strcmp(app.cities, newCity))

app.cities{end+1} = newCity;

app.CityDropDown.Items = app.cities;

end

end

end

% Callbacks that handle component events

methods (Access = private)

% Button pushed function: AddCityButton

function AddCityButtonPushed(app, event)

app.addCity();

end

% Button pushed function: GetInfoButton

function GetInfoButtonPushed(app, event)

app.updateWeatherData();

end

end

% Component initialization

methods (Access = private)

% Create UIFigure and components

function createComponents(app)

% Create UIFigure and hide until all components are created

app.UIFigure = uifigure('Visible', 'off');

app.UIFigure.Position = [100 100 1136 581];

app.UIFigure.Name = 'MATLAB App';

% Create UIAxes

app.UIAxes = uiaxes(app.UIFigure);

title(app.UIAxes, 'Title')

xlabel(app.UIAxes, 'X')

ylabel(app.UIAxes, 'Y')

zlabel(app.UIAxes, 'Z')

app.UIAxes.Position = [25 370 300 185];

% Create UIAxes2

app.UIAxes2 = uiaxes(app.UIFigure);

title(app.UIAxes2, 'Title')

xlabel(app.UIAxes2, 'X')

ylabel(app.UIAxes2, 'Y')

zlabel(app.UIAxes2, 'Z')

app.UIAxes2.Position = [403 370 300 185];

% Create UIAxes3

app.UIAxes3 = uiaxes(app.UIFigure);

title(app.UIAxes3, 'Title')

xlabel(app.UIAxes3, 'X')

ylabel(app.UIAxes3, 'Y')

zlabel(app.UIAxes3, 'Z')

app.UIAxes3.Position = [790 370 300 185];

% Create CityDropDownLabel

app.CityDropDownLabel = uilabel(app.UIFigure);

app.CityDropDownLabel.HorizontalAlignment = 'right';

app.CityDropDownLabel.Position = [678 231 89 22];

app.CityDropDownLabel.Text = 'City Drop Down';

% Create CityDropDown

app.CityDropDown = uidropdown(app.UIFigure);

app.CityDropDown.Position = [782 231 99 22];

% Create CityEditFieldLabel

app.CityEditFieldLabel = uilabel(app.UIFigure);

app.CityEditFieldLabel.HorizontalAlignment = 'right';

app.CityEditFieldLabel.Position = [123 231 79 22];

app.CityEditFieldLabel.Text = 'City Edit Field';

% Create CityEditField

app.CityEditField = uieditfield(app.UIFigure, 'text');

app.CityEditField.Position = [217 231 100 22];

% Create AddCityButton

app.AddCityButton = uibutton(app.UIFigure, 'push');

app.AddCityButton.ButtonPushedFcn = createCallbackFcn(app, @AddCityButtonPushed, true);

app.AddCityButton.Position = [324 231 100 23];

app.AddCityButton.Text = 'Add City';

% Create GetInfoButton

app.GetInfoButton = uibutton(app.UIFigure, 'push');

app.GetInfoButton.ButtonPushedFcn = createCallbackFcn(app, @GetInfoButtonPushed, true);

app.GetInfoButton.Position = [519 108 100 23];

app.GetInfoButton.Text = 'Get Info';

% Show the figure after all components are created

app.UIFigure.Visible = 'on';

end

end

% App creation and deletion

methods (Access = public)

% Construct app

function app = app2

% Create UIFigure and components

createComponents(app)

% Register the app with App Designer

registerApp(app, app.UIFigure)

if nargout == 0

clear app

end

end

% Code that executes before app deletion

function delete(app)

% Delete UIFigure when app is deleted

delete(app.UIFigure)

end

end

end

ERRORS :

Error using fetchFiveDayForecast

Dot indexing is not supported for variables of this type.

Error in fetchFiveDayForecast (line 19)

data(i).dt = datetime(list(i).dt_txt, 'InputFormat', 'yyyy-MM-dd HH:mm:ss', 'Format', 'yyyy-MM-dd HH:mm:ss', 'TimeZone', 'UTC');

Error in app2/updateWeatherData (line 27)

weatherData = fetchFiveDayForecast(selectedCity, app.apiKey);

Error in app2/GetInfoButtonPushed (line 68)

app.updateWeatherData();

Error in matlab.apps.AppBase>@(source,event)executeCallback(ams,app,callback,requiresEventData,event) (line 62)

newCallback = @(source, event)executeCallback(ams, ...

Error while evaluating Button PrivateButtonPushedFcn.

[Image Analyst]

You already posted this question before and we said it was likely that you had not initialized the "list" variable. Make it easy for people to run your code by attaching the .mlapp files with the paperclip icon.

Answer 1

[SACHIN KHANDELWAL]

Hi @Yunus Emre,

I had a brief look into the code that you provided, and I identified where the issue originates. In the function "fetchFiveDayForecast", the response you receive from webread is actually a cell array. To access the data from this cell array, you need to use "{}" braces instead of "()". After making this change to the "list", you should be able to continue with your workflow seamlessly.

You may want to take a look at the following working code.

function weatherData = uv()
    apiKey = '8837203c2a21882aa541f6d408e564ab';
    city = 'Adana';
    baseUrl = 'https://api.openweathermap.org/data/2.5/forecast';
    url = sprintf('%s?q=%s&appid=%s&units=metric', baseUrl, city, apiKey);
    response = webread(url);
    % Process JSON data
    if isfield(response, 'list')
        list = response.list;  % list is a cell array
    else
        error('Invalid response structure');
    end
    % Initialize data struct
    data = struct();
    numEntries = length(list);
    
    % Loop through each entry in the list and extract data
    for i = 1:numEntries
        % to access the data from cell array, use {} instead of ()
        %% list(i) will give you again an cell array with struct.
        %% list{1} will give you the struct data
        data(i).dt = datetime(list{i}.dt_txt, 'InputFormat', 'yyyy-MM-dd HH:mm:ss', 'Format', 'yyyy-MM-dd HH:mm:ss', 'TimeZone', 'UTC');
        data(i).temp = list{i}.main.temp;
        data(i).humidity = list{i}.main.humidity;
        data(i).windSpeed = list{i}.wind.speed;
    end
    
    % Store the data in the output structure
    weatherData = struct();
    weatherData.dt = [data.dt];
    weatherData.temp = [data.temp];
    weatherData.humidity = [data.humidity];
    weatherData.windSpeed = [data.windSpeed];
end

I hope this is helpful.

Thanks!