Seeking Assistance in Using a GUI to Return Text From A Webpage

Hello!

I am currently developing a MATLAB GUI using App Designer. The premise for this app is that users will able to select 1/5 cities using a dropdown menu. After completing their selection, a button next to the dropdown menu will be coded with a callback function that: (PART 1) returns the html code for the city's 7-day forecast in an editable text field below; and (PART 2) returns the text from the forecast in a multiline text area. See the photos below for reference:

This is the code I have for PART 1 and it seems to work fine:

        % Button pushed function: SEARCHWEBButton
        function SEARCHWEBButtonPushed(app, event)
         app.geosearch = app.CityDropDown.Value;
         
         app.TORn = 'Toronto';
         app.OTTn = 'Ottawa';
         app.MISSn = 'Mississauga';
         app.BRMPn = 'Brampton';
         app.HMLTn = 'Hamilton';
            
         app.TORu = 'https://weather.gc.ca/city/pages/on-143_metric_e.html';
         app.OTTu = 'https://weather.gc.ca/city/pages/on-118_metric_e.html';
         app.MISSu = 'https://weather.gc.ca/city/pages/on-24_metric_e.html';
         app.BRMPu = 'https://www.weather.gc.ca/city/pages/on-4_metric_e.html';
         app.HMLTu = 'https://weather.gc.ca/city/pages/on-77_metric_e.html';
            
         % Concatenate City Names & URLs
         app.CityName = {app.TORn;app.OTTn;app.MISSn;app.BRMPn;app.HMLTn};
         app.CityURL = {app.TORu; app.OTTu; app.MISSu; app.BRMPu; app.HMLTu};
            
         %Join Cities and URLS
         app.CityLgd = [app.CityName app.CityURL];
            
         %Index Cell Array for Search Term
         app.s01 = app.geosearch;
         app.s02 = app.CityLgd(:,1);
            
         app.tf = strcmpi(app.s01,app.s02);
         app.tf = find(app.tf);
         app.index = app.tf;
            
         app.sURL = char(app.CityLgd(app.index,2));
         
         app.WeatherCANLinkEditField.Value = app.sURL;

The following code is what I have for completing PART 2 (returning the text from the weather report):

         url = app.sURL;
         code = webread(url);
         app.RetrievedDataTextArea.Value = extractHTMLText(code);

However, it seems to fail with each trial. Is there a way to code the GUI to return text from an external HTML page?

[Mario Malic]

Hello,

One of the Stuart's blog posts https://blogs.mathworks.com/videos/2020/11/13/scraping-links-from-a-list-of-web-pages/ is about extracting links from the web page, which may help you in getting the text.

[Chedi Mbaga]

Many thanks for the guidance @Mario Malic! I'll be sure to visit the link.

Answer 1

[Sourabh Kondapaka]

Hi @Chedi Mbaga,

The below code can be used as a reference for extracting the data about temperatures:

url = 'https://weather.gc.ca/city/pages/on-143_metric_e.html';
data = webread(url);
tree = htmlTree(data);
pTags = findElement(tree,'p');
textContent = extractHTMLText(pTags);

As @Mario Malic suggested please go through the blog post.

Documentation links:

• getAttribute()
• findElement()
• Parse HTML Text and Extract Content
• htmlTree()

Similar questions have been answered in the community:

• link1
• link2

[Chedi Mbaga]

Thank you so much @Sourabh Kondapaka for the assistance! I had been grappling with this challenge for a while and the code you provided offers the exact functionalities I was looking for.